The Stenian-Cambrian Tectonic Evolution of Central Madagascar

Donnelly Brian Archibald

Department of Earth Sciences School of Physical Sciences The University of Adelaide

May 2016

Table of Contents Abstract v List of figures vi List of tables ix List of supplementary appendices xi Declaration xii Journal Articles xiii Acknowledgements xiv

Chapter 1 – Introduction and Geology of Madagascar 1 1.1 Introduction 2 1.2 Project outline 2 1.3 Project aims and hypotheses 8 1.4 Regional geology of Madagascar 10 1.5 Thesis outline 12

Chapter 2 – The Ambatolampy Group 15 Statement of Authorship 16 Abstract 18 2.1 Introduction 18 2.2 Regional geology of Madagascar 19 2.3 The Ambatolampy Group 22 2.3.1 Group description 22 2.3.2 Lithologies and stratigraphy 23 2.3.3 Previous work and interpretation 23 2.4 Analytical Methods 23 2.4.1 Zircon separation and imaging 23 2.4.2 Zircon U-Pb geochronology 24 2.4.3 Zircon oxygen isotope analysis 24 2.4.4 Zircon Lu-Hf analysis 24 2.5 Sample information and results 25 2.6 Discussion 32 2.6.1 Depositional age constraints of the Ambatolampy Group Protoliths 32 2.6.2 18O in the Ambatolampy Group 33 2.6.3 Relationship to metasedimentary units in central Madagascar 33 2.6.4 Provenance and potential source regions for the Ambatolampy Group 37 2.7 Summary and conclusions 38 i

2.8 Acknowledgements 39

Chapter 3 – Zircon isotopic characteristics of the Imorona-Itsindro Suite 41 Statement of Authorship 42 Abstract 44 3.1 Introduction 44 3.2 Regional geology of Madagascar 45 3.3 The Imorona-Itsindro Suite 49 3.3.1 Suite description and contact relationships 49 3.3.2 Previous isotopic work 50 3.4 Analytical methods 51 3.5 Results 54 3.5.1 Sample description and U-Pb zircon results 54 3.5.1.1 Ikalamavony Domain 54 3.5.1.2 Itremo Domain 55 3.5.1.3 Central Antananarivo Domain 55 3.5.1.4 Northern Antananarivo Domain 58 3.5.1.5 Eastern Antananarivo Domain 59 3.5.1.6 Masora Domain 64 3.5.2 Oxygen and hafnium isotope results 64 3.5.1.1 Ikalamavony Domain 64 3.5.1.2 Itremo Domain 64 3.5.1.3 Central Antananarivo Domain 65 3.5.1.4 Northern Antananarivo Domain 65 3.5.1.5 Eastern Antananarivo Domain 66 3.5.1.6 Masora Domain 67 3.6 Discussion 68 3.6.1 Zircon U-Pb geochronological data for the Imorona-Itsindro Suite 68 3.6.2 Oxygen and hafnium isotopes in the Imorona-Itsindro Suite 69 3.6.3 Temporal and spatial distribution of the Imorona-Itsindro Suite 72 3.6.4 Tectonic implications 74 3.7 Summary and conclusions 77 3.8 Acknowledgements 78

Chapter 4 – Geochemistry of the Imorona-Itsindro Suite 79 Statement of Authorship 80 Abstract 81 ii

4.1 Introduction 81 4.2 Regional geology of Madagascar 83 4.3 Analytical methods 85 4.4 Results 86 4.4.1 Field descriptions and contact relationships 86 4.4.2 Petrography and mineral chemistry 86 4.4.3 Whole-rock geochemistry 95 4.5 Discussion 106 4.5.1 Petrogenesis of the Imorona-Itsindro Suite 106 4.5.2 Tectonic implications 112 4.5.3 Implications for the tectonic development of central Madagascar 115 4.6 Summary and conclusions 117 4.7 Acknowledgements 118

Chapter 5 – Geochemistry of the Ambalavao-Maevarano Suite 119 Statement of Authorship 120 Abstract 121 5.1 Introduction 121 5.2 Regional geological context 123 5.3 Geology of Madagascar 123 5.3.1 Lithotectonic domains and unit descriptions 123 5.3.2 Structural and metamorphic context 127 5.4 Field relationships and previous work 128 5.4.1 Ambalavao Suite 128 5.4.2 Maevarano Suite 129 5.5 Analytical methods 130 5.6 Results 131 5.6.1 Sample descriptions and U-Pb geochronology 131 5.6.1.1 Ambalavao Suite in the Antananarivo Domain 131 5.6.1.2 Ambalavao Suite in the Itremo Domain 133 5.6.1.3 Ambalavao Suite in the Ikalamavony Domain 134 5.6.1.4 Maevarano Suite in the Antananarivo Domain 135 5.6.2 Oxygen isotopes 135 5.6.2.1 Ambalavao Suite 135 5.6.2.2 Maevarano Suite 135 5.6.3 Hafnium isotopes 137 5.6.3.1 Ambalavao Suite 137 iii

5.6.3.2 Maevarano Suite 139 5.6.4 Whole-rock geochemistry 140 5.6.4.1 Ambalavao Suite 140 5.6.4.2 Maevarano Suite 140 5.7 Discussion 142 5.7.1 Age of the Ambalavao and Maevarano Suites 142 5.7.2 Oxygen and hafnium isotopes 145 5.7.3 Genesis of the Ambalavao and Maevarano Suites 147 5.8 Summary and conclusions 150 5.9 Acknowledgements 151

Chapter 6 – The Dabolava Suite 153 Statement of Authorship 154 Abstract 155 6.1 Introduction 155 6.2 Regional geology of Madagascar and Neoproterozoic tectonic development 158 6.3 The Dabolava Suite 161 6.4 Analytical methods 161 6.5 Results 162 6.5.1 Petrography 162 6.5.2 U-Pb geochronology 163 6.5.3 Oxygen and hafnium isotopes 167 6.5.4 Whole-rock geochemistry 168 6.6 Discussion 169 6.6.1 U-Pb age and zircon isotopes 169 6.6.2 Petrogenesis of the Dabolava Suite 175 6.6.3 Implications for Neoproterozoic tectonics in Madagascar 176 6.6.4 Implications for the amalgamation of Rodinia 180 6.7 Summary and conclusions 181 6.8 Acknowledgements 182

Chapter 7 – Summary and conclusions 183 7.1 The Proterozoic tectonic evolution of central Madagascar 184

Chapter 8 - References 189

Abstract

Madagascar occupies an important location in many Proterozoic plate reconstructions. It lies within the East African Orogen, which involves a collage of Proterozoic microcontinents and arc terranes wedged between older cratonic units during Gondwana assembly. Oceanic crust is an important component of palaeogeographic reconstructions that is often overlooked because exposures of in situ oceanic crust older than ~200 Myr do not exist. Therefore, studies of ancient oceanic crust require proxies such as analysing the products of magmatic arcs. The Malagasy basement preserves five magmatic suites emplaced consecutively from ~1100-500 Ma. During this time, the Rodinia supercontinent amalgamated then dispersed and the Gondwana supercontinent formed. This whole-rock geochemical and zircon isotopic study attempts to unravel the Proterozoic tectonic history of central Madagascar using the tectonic setting and duration of various Stenian to Cambrian magmatic episodes. These magmatic suites are the ~1080-980 Ma (Dabolava Suite), ~850-750 Ma (Imorona-Itsindro Suite) and ~650-520 Ma (Kiangara, Ambalavao and Maevarano Suites). Gabbroic and granitoid rocks of the Dabolava Suite combined with the coeval Ikalamavony Group represent a magmatic arc and volcano-sedimentary sequence deposited in an oceanic-arc environment based on isotopic and geochemical characteristics. The Imorona-Itsindro Suite represents contemporaneous emplacement of various lithologies from gabbro to granitoids and syenite. Oxygen and hafnium isotope data have a broad inverse relationship with apparent magmatic cycles occurring on the scale of ~15-40 Ma that emphasize periods of significant supracrustal assimilation evolving to “mantle-like” (or below) signatures. The spatial distribution of isotopic data indicates that the isotopic character of Tonian-aged zircon replicates the basement domain into which the magmas intruded. Samples intruding the Ikalamavony Domain exhibit a less evolved Hf(t) isotopic signature than Tonian-aged rocks intruding the domains to the east, implying melting of different source material. The zircon isotopic dataset emphasises the age range and composition of the Tonian lithosphere beneath central Madagascar. Geochemically, mid-Tonian rocks are calc-alkaline with trace-element characteristics consistent with a continental arc genesis. Radiogenic isotope data show evolved Sr and Nd signatures. Changes in subduction zone dynamics, crustal anatexis and crustal assimilation of the diverse basement domains into ascending magmas contributed to geochemical variations. Prolonged subduction (>100 Myr) provided sufficient time for the arc to mature and a shallow (<100km), metasomatised spinel lherzolite mantle source is preferred. The isotopic and geochemical characteristics of the Imorona-Itsindro Suite argue for a collective genesis in a supra-subduction zone tectonic setting with the Neoproterozoic suture located west of the Ikalamavony Domain. The Ediacaran to Cambrian Kiangara, Ambalavao and Maevarano Suites are post-collisional, mainly granitoid suites emplaced during the final assembly of Gondwana. Magmas incorporated crustal material and isotopic signatures reflect the basement unit in which samples intrude and these rocks are related spatially and temporally with major late-Neoproterozoic deformation episodes. Collectively, these data identify a previously unrecognised and long-lived (~500 Ma) active continental margin correlative to the present-day Pacific Ocean margin. Understanding this large dataset is critical for understanding Madagascar’s tectonic evolution during the Stenian to Cambrian.

List of Figures

Chapter 1 Fig. 1.1 Palaeogeographic reconstruction of (a) Rodinia and (b) Gondwana 3 Fig. 1.2 Simplified basement geology of Madagascar 5

Chapter 2 Palaeogeographic reconstruction of the Neoproterozoic continents in Fig. 2.1 Gondwana showing the location of the present study and the regional 20 geology of Madagascar Geologic map of central Madagascar showing the distribution of the Fig. 2.2 21 Ambatolampy Group and sampling locations Cathodoluminescence images for representative zircon (<10% Fig. 2.3 28 discordant) from the Ambatolampy Group Tera-Wasserburg concordia diagrams for Ambatolampy Group U-Pb Fig. 2.4 30 data Probability density plots for detrital zircon from the Ambatolampy Fig. 2.5 31 Group Plot of the 207Pb/206Pb (zircon) age versus 18O for Ambatolampy Group Fig. 2.6 31 samples  (t) plotted against the 207Pb/206Pb (zircon) age for samples from the Fig. 2.7 Hf 32 Ambatolampy Group Comparative U-Pb age of detrital zircon probability density diagrams for Fig. 2.8 34 metasedimentary units in central Madagascar

Chapter 3 Palaeogeographic reconstruction of the Neoproterozoic continents in Fig. 3.1 Gondwana showing the location of the present study and the regional 46 geology of Madagascar Geological map of central Madagascar showing the extent of Tonian Fig. 3.2 47 magmatism sampled in this study

Fig. 3.3 Representative field photographs of the Imorona-Itsindro Suite 50

Selected cathodoluminescence images for representative zircon from the Fig. 3.4 54 Imorona-Itsindro Suite Concordia diagrams showing zircon analyses for Tonian samples Fig. 3.5 56 intruding the Ikalamavony and Itremo Domains Concordia diagrams showing zircon analyses for Tonian samples Fig. 3.6 58 intruding the Central Antananarivo Domain Concordia diagrams showing zircon analyses for Tonian samples Fig. 3.7 intruding the Northern Antananarivo, Eastern Antananarivo and Masora 60 Domains 18O plotted against the interpreted crystallisation age for analyses of Fig. 3.8 66 Imorona-Itsindro Suite samples  (t) plotted against the interpreted crystallisation age for analyses of Fig. 3.9 Hf 67 Imorona-Itsindro Suite samples

Histogram and probability density plot of all reliable (as indicated in the text) magmatic crystallisation ages for the Imorona-Itsindro Suite Fig. 3.10 70 intruding the Masora, Antananarivo, Tsaratanana, Itremo, and Ikalamavony Domains in Madagascar Plot of (a) 18O and (b)  (t) plotted against the interpreted Fig. 3.11 Hf 73 crystallisation age for all Tonian zircon analysed in this study Longitudinal coordinates plotted against (a) the interpreted 18 Fig. 3.12 crystallisation age, (b)  O, and (c) Hf(t) for all zircon in central 75 Madagascar with Tonian crystallisation ages between ~850 and 750 Ma

18 Fig. 3.13 Plot of  O versus Hf(t) for all zircon analysed in this study 76

Chapter 4 Palaeogeographic reconstruction of the Neoproterozoic continents in Fig. 4.1 Gondwana showing the location of the present study and the regional 82 geology of Madagascar Geological map of central Madagascar showing the extent of Tonian- Fig. 4.2 85 aged magmatism sampled in this study Plutonic rock classification diagram plotting samples of the Imorona- Fig. 4.3 87 Itsindro Suite collected in this study using modal mineralogy Fig. 4.4 Representative outcrop photographs of the Imorona-Itsindro Suite 88 Representative photomicrographs for samples of the Imorona-Itsindro Fig. 4.5 89 Suite Fig. 4.6 Mineral compositions from EPMA analyses 103 Harker major element variation diagrams for major element oxides, Fig. 4.7 103 showing the extent of fractionation in the Imorona-Itsindro Suite Fig. 4.8 Chondrite-normalized REE diagrams 104 Fig. 4.9 MORB normalised trace-element spider diagrams 105 Plutonic rock classification diagram using normative mineralogy for all Fig. 4.10 108 Imorona-Itsindro Suite samples (n=355) Tectonic setting and classification diagrams for samples of the Imorona- Fig. 4.11 110 Itsindro Suite Fig. 4.12 Radiogenic isotope plots for samples of the Imorona-Itsindro Suite 111 Major and trace-element data for the Imorona-Itsindro Suite plotted Fig. 4.13 against reference datasets from the GEOROC Database for the Andes 115 and the East African Rift Geochemical data plotted against longitudinal coordinates for samples of Fig. 4.14 117 the Imorona-Itsindro Suite

Chapter 5 Palaeogeographic reconstruction of the Neoproterozoic continents in Fig. 5.1 Gondwana showing the location of the present study and regional 122 geology of Madagascar Geological map of central Madagascar showing the extent of Ediacaran- Fig. 5.2 124 Cambrian magmatism sampled in this study Representative field photographs of the Ambalavao and Maevarano Fig. 5.3 128 Suites Quartz-Alkali-feldspar-Plagioclase (QAP) diagram for the Ambalavao Fig. 5.4 130 and Maevarano Suites using the normative mineralogy Cathodoluminescence (CL) images for representative zircon from the Fig. 5.5 132 Ambalavao and Maevarano Suites Fig. 5.6 Concordia diagrams showing zircon analyses from the Ambalavao Suite 134 vii

Concordia diagrams showing zircon analyses from the Ambalavao and Fig. 5.7 137 Maevarano Suites Fig. 5.8 Field photographs of the sampling location of DA14-126 138 Oxygen and hafnium isotope diagrams for samples of the Ambalavao Fig. 5.9 139 and Maevarano Suites Harker major element variation diagrams for various major element oxides, showing the extent to which Ambalavao and Maevarano Suite Fig. 5.10 142 samples are fractionated and the degree of compositional overlap between the two suites Chondrite-normalized REE diagrams and primitive mantle normalised Fig. 5.11 trace-element spider diagrams for samples of the Ambalavao and 143 Maevarano Suites Kernel density plot of U-Pb age data for all available geochronology Fig. 5.12 144 data for late Cryogenian to Cambrian magmatism in Madagascar Tectonic setting and classification diagrams for samples of the Fig. 5.13 149 Ambalavao and Maevarano Suites

Chapter 6 Simplified basement geology of Madagascar showing the major tectonic Fig. 6.1 157 domains and shear zones Geologic map of the Ikalamavony Domain and the western margin of Fig. 6.2 the Antananarivo Domain showing the extent of Stenian-Tonian 159 magmatism sampled in this study Fig. 6.3 Representative field photographs of the Dabolava Suite 163 Cathodoluminescence (CL) images for representative zircon from the Fig. 6.4 165 Dabolava Suite Fig. 6.5 Concordia diagrams showing zircon analyses from the Dabolava Suite 166 Oxygen and hafnium isotope diagrams for five samples of the Dabolava Fig. 6.6 168 Suite Fig. 6.7 Harker major element variation diagrams for the Dabolava Suite 173 Chondrite-normalized REE diagrams and primitive mantle normalised Fig. 6.8 173 multi-element variation diagrams for samples of the Dabolava Suite Tectonic setting and classification diagrams for samples of the Dabolava Fig. 6.9 175 Suite Major and trace-element data for the Dabolava Suite and Ikalamavony Fig. 6.10 Group amphibolite plotted against reference datasets from the GEOROC 177 Database for the Andes continental arc and the Aleutian Arc Palaeogeographic reconstruction of the Rodinia Supercontinent at ~900 Ma and tectonic cartoon illustrating the development of magmatic arcs Fig. 6.11 181 in the Mozambique Ocean with emphasis on those also involved in the East African Orogen near Madagascar (Azania)

Appendices Fig. A.6.1 Results of Plešovice zircon standard analyses 388

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List of Tables

Chapter 2 Table 2.1 Summary of standard data collected for each method in this study 25 Table 2.2 Summary of sample locations, rock characteristics and mineralogy 27 Physical and optical characteristics of zircon from the Ambatolampy Table 2.3 29 Group

Chapter 3 Summary of the major tectonic elements of central and northern Table 3.1 Madagascar with the approximate age of each sedimentary unit or 48 magmatic suite Summary of sample names, lithology, locations and mineralogy for Table 3.2 52 samples of the Imorona-Itsindro Suite

Physical and optical characteristics of zircon from the Imorona-Itsindro Table 3.3 53 Suite Summary of U-Pb data collected by BGS-USGS-GLW (2008) re- Table 3.4 59 examined in this study Summary of U-Pb data and age deductions for Tonian rocks in central Table 3.5 61 Madagascar Summary of all Imorona-Itsindro Suite zircon U-Pb, 18O, and  (t) Table 3.6 Hf 68 isotopic data

Chapter 4 Summary of sample names, lithology, locations and geographical Table 4.1 90 reference for samples of the Imorona-Itsindro Suite Table 4.2 Petrographic summary of samples from the Imorona-Itsindro Suite 91 Representative mineral chemistry (in wt. %) for alkali-feldspar from the Table 4.3 93 Imorona-Itsindro Suite Representative mineral chemistry (in wt. %) for plagioclase from the Table 4.4 94 Imorona-Itsindro Suite Representative mineral chemistry (in wt. %) for feldspar exsolution Table 4.5 95 lamellae from the Imorona-Itsindro Suite Representative mineral chemistry (in wt. %) for amphibole from the Table 4.6 96 Imorona-Itsindro Suite Representative mineral chemistry (in wt. %) for biotite from the Table 4.7 97 Imorona-Itsindro Suite Representative mineral chemistry (in wt. %) for biotite from the Table 4.8 98 Imorona-Itsindro Suite Major and trace element geochemical data collected in this study from the Imorona-Itsindro Suite. Eu/Eu*, La /Sm and Tb /Lu ratios were Table 4.9 N N N N 99 calculated using chondrite normalising values from Sun and McDonough (1989). Table 4.10 Nd, Sm, and Sr isotope data 107

Chapter 5 Summary of sample names, lithology, locations and geographical Table 5.1 131 reference for samples of the Ambalavao and Maevarano Suites Physical and optical characteristics of zircon from the Ambalavao and Table 5.2 132 Maevarano Suites Summary of U-Pb data and age deductions for the Ambalavao and Table 5.3 136 Maevarano Suites in central Madagascar Summary of U-Pb, O, and Hf isotope data collected for samples of the Table 5.4 139 Ambalavao and Maevarano Suites in this study Major and trace element geochemical data collected in this study from Table 5.5 141 the Ambalavao and Maevarano Suites

Chapter 6 Summary of sample names, locations, lithology and mineralogy for Table 6.1 164 samples of the Dabolava Suite Table 6.2 Physical and optical characteristics of zircon from the Dabolava Suite 165 Table 6.3 SHRIMP II oxygen isotope results from zircon 170 Table 6.4 MC-LA-ICP-MS hafnium isotope results from zircon 171 Major and trace element geochemical data collected in this study from Table 6.5 172 the Dabolava Suite Table 6.6 Summary of zircon U-Pb, oxygen and hafnium isotope results 174

Appendices Summary of standard data collected for each method in this study during Table A.3.1 231 Imorona-Itsindro Suite zircon analyses

Detection limits for major element oxides, minor and trace elements Table A.4.1 289 analysed in this study

Summary of standard data collected for each method in this study during Table A.5.1 359 Ambalavao and Maevarano Suite zircon analyses

Detection limits for major element oxides, minor and trace elements Table A.5.2 360 analysed in this study

Summary of standard data collected for each method in this study during Table A.6.1 389 Dabolava Suite zircon analyses

Detection limits for major element oxides, minor and trace elements Table A.6.2 391 analysed in this study

Supplementary Appendices

Appendix 2.1 - Ambatolampy Group U-Pb (zircon) data 208 Appendix 2.2 - Ambatolampy Group oxygen isotope (zircon) data 222 Appendix 2.3 - Ambatolampy Group hafnium isotope (zircon) data 225

Appendix 3.1 - Genesis of the Imorona-Itsindro Suite analytical methods 229 Appendix 3.1.1 - Sample collection and processing 230 Appendix 3.1.2 - U-Pb (zircon) geochronology 230 Appendix 3.1.3 - Oxygen isotopes in zircon 230 Appendix 3.1.4 - Hafnium isotopes in zircon 231 Appendix 3.2 - Imorona-Itsindro Suite U-Pb (zircon) data 233 Appendix 3.3 - Imorona-Itsindro Suite oxygen isotope (zircon) data 275 Appendix 3.4 - Imorona-Itsindro Suite hafnium isotope (zircon) data 281

Appendix 4.1 - Petrogenesis of the Imorona-Itsindro Suite analytical methods 286 Appendix 4.1.1 - Sample collection and processing 287 Appendix 4.1.2 - Petrography and mineral chemistry 287 Appendix 4.1.3 - Whole-rock geochemistry 287 Appendix 4.1.4 - Sm-Nd and Sr isotope analysis 287 Appendix 4.2 - Petrogenesis of the Imorona-Itsindro Suite EMPA mineral data 290 Appendix 4.2.1 - Representative mineral chemistry for alkali-feldspar 291 Appendix 4.2.2 - Representative mineral chemistry for plagioclase 302 Appendix 4.2.3 - Representative mineral chemistry for feldspar exsolution lamellae 312 Appendix 4.2.4 - Representative mineral chemistry for biotite 316 Appendix 4.2.5 - Representative mineral chemistry for amphibole 332 Appendix 4.2.6 - Representative mineral chemistry for clinopyroxene 348 Appendix 4.2.7 - Representative mineral chemistry for titanite 350 Appendix 4.2.8 - Representative mineral chemistry for garnet 353

Appendix 5.1 - Genesis of the Ambalavao and Maevarano Suites analytical methods 357 Appendix 5.1.1 - Sample collection and processing 358 Appendix 5.1.2 - U-Pb (zircon) geochronology 358 Appendix 5.1.3 - Oxygen isotopes in zircon 358 Appendix 5.1.4 - Hafnium isotopes in zircon 358 Appendix 5.1.5 - Whole-rock geochemistry 359 Appendix 5.2 - Ambalavao and Maevarano Suite U-Pb (zircon) data 361 Appendix 5.3 - Ambalavao and Maevarano Suite oxygen isotope (zircon) data 379 Appendix 5.4 - Ambalavao and Maevarano Suite hafnium isotope (zircon) data 382

Appendix 6.1 - Genesis of the Dabolava Suite analytical methods 387 Appendix 6.1.1 - Sample collection and processing 388 Appendix 6.1.2 - U-Pb (zircon) geochronology 388 Appendix 6.1.3 - Oxygen isotopes in zircon 389 Appendix 6.1.4 - Hafnium isotopes in zircon 389 Appendix 6.1.5 - Whole-rock geochemistry 390 Appendix 6.2 - Dabolava Suite U-Pb (zircon) data 392

Declaration

I certify that this work contains no material which has been accepted for the award of any other degree or diploma in my name, in any university or other tertiary institution and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference has been made in the text. In addition, I certify that no part of this work will, in the future, be used in a submission in my name, for any other degree or diploma in any university or other tertiary institution without the prior approval of the University of Adelaide and where applicable, any partner institution responsible for the joint-award of this degree.

I give consent to this copy of my thesis when deposited in the University Library, being made available for loan and photocopying, subject to the provisions of the Copyright Act 1968.

The author acknowledges that copyright of published works contained within this thesis resides with the copyright holder(s) of those works.

I also give permission for the digital version of my thesis to be made available on the web, via the University’s digital research repository, the Library Search and also through web search engines, unless permission has been granted by the University to restrict access for a period of time.

______

Donnelly B. Archibald

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Journal Articles

Archibald, D.B., Collins, A.S., Foden, J.D., Payne, J.L., Taylor, R., Holden, P., Razakamanana, T., Clark, C., 2015. Towards unravelling the Mozambique Ocean conundrum using a triumvirate of zircon isotopic proxies on the Ambatolampy Group, central Madagascar. Tectonophysics 662, 167-182.

Archibald, D.B., Collins, A.S., Foden, J.D., Payne, J.L., Holden, P., Razakamanana, T., De Waele, B., Pitfield, P.E.J., Thomas, R.J., 2016. Genesis of the Tonian Imorona-Itsindro Magmatic Suite in central Madagascar: Insights from U-Pb, oxygen and hafnium isotopes in zircon. Precambrian Research 281, 312-337.

Archibald, D.B., Collins, A.S., Foden, J.D., Razakamanana, T. under review. Petrogenesis of the Tonian Imorona-Itsindro Suite. Journal of Geology.

Archibald, D.B., Collins, A.S., Foden, J.D., Payne, J.L., Holden, P., Razakamanana, T. under review. Tectonics and chemistry of late to post tectonic magmatism in the Malagasy Mozambique Belt. Lithos

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Acknowledgements

I would like to extend my gratitude to Prof Alan Collins for his guidance and encouragement during the course of my PhD. Most of all, I would like to thank him for the opportunities to experience exotic cultures in new countries while completing my project. These opportunities have made me a better geologist and scientist by providing me with the opportunity to travel around Australia and the world. I would also like to thank my co-supervisor Emeritus Prof John Foden for his insight, guidance and support especially when trying to understand and interpret geochemical and isotopic data.

This project would not have been possible if not for Prof Theodore Razakamanana from the University of Toliara, Madagascar. His upbeat personality, knowledge of the Madagascan geology and technical assistance in the field made for two enjoyable field seasons.

The Razafinjoelina family, in particular Auguste and Berthieu are thanked for providing transportation, assistance in the field, and their hospitality during fieldwork in Madagascar.

I would like to thank my co-authors, Dr. Justin Payne for his assistance acquiring hafnium isotopic data and for careful manuscript editing. David Bruce is recognised for his assistance acquiring Sr and Nd-Sm isotopic data and Dr. Peter Holden for his assistance acquiring oxygen isotopic data. Dr. Richard Taylor and Dr. Chris Clark are thanked for their assistance acquiring SHRIMP U-Pb data.

I would also like to thank several members of the PGRM project including Bert De Waele, Bob Thomas and Peter Pitfield for providing samples and for providing alternative interpretations on the geology of central Madagascar. The staff at Adelaide Microscopy, in particular, Dr. Ben Wade, Ms. Aoife McFadden, and Mr. Angus Netting are acknowledged for their technical assistance when acquiring analytical data. Dr. Diana Plavsa is recognised for her assistance helping me get this project started.

I would like to acknowledge the University of Adelaide geology faculty for their support over the past three years. I would especially like to thank Dr. Rosalind King, Dr. Stijn Glorie, Dr. Dave Kelsey, Dr. Katie Howard and Dr. Graham Heinson for allowing me to learn and develop my teaching skills while demonstrating undergraduate practicals.

My “officemates” Katherine and Morgan made walking into Mawson everyday entertaining. I would not have made it to Australia if it were not for Bonnie Henderson visiting Canada and convincing me Adelaide was worth moving half-way around the world. I thank Lachlan for giving me a place to live when I arrived and for not kicking me out for almost 2 years! Funny and Stijn moved to Australia at the same time as I did and they made the transition a lot easier. Funny’s cooking made my early days feel like home. Finally, I would like to thank Francesco and the rest of the PhD cohort at Adelaide (both new and old) for their friendship and support over the past 3+ years.

Last and certainly not least, finishing this project would not have been possible without the love and support of my Canadian Family and my new Australian Family. It was difficult to move to Adelaide but Maggie, Brian, Daniel, Amanda and the rest of my friends and family supported me every step of the way. My second family (Kath, Steve, Annie, Bruce, Joan and Theo) in Australia made being away from home easier and fun. Eliza, for being there with me during all of the fun times and difficult times I am forever grateful to you. Hopefully, we will have many more adventures together as we begin our next chapter in Canada.

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