“Advancement in petrography and microstratig- raphy as proxies of climate and environmental changes”

VALENTINA VANGHI

(ORCID: 0000-0002-9412-6602)

BSc. Natural Science (Hons.) (University of Florence, )

MSc. Quaternary Geology (University of the Basque Country, Spain)

MSc. Evolution (University of Burgos, Spain)

A Thesis submitted in fulfilment of the requirements for a degree of

DOCTOR OF PHILOSOPHY

March 2018

School of Environmental and Life Science

Faculty of Science and Information Technology

University of Newcastle, New South Wales, Australia

Statement of Originality

I declare this Thesis contains no material which has been accepted, or is being examined, for the award of any other degree or diploma 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. I give consent to the final version of my thesis being made available worldwide when deposited in the University’s Digital Repository, subject to the provisions of the Copyright Act 1968 and any approved embargo.

Acknowledgement of Collaboration

I hereby certify that the work embodied in this Thesis has been done in collaboration with other researchers, or carried out in other institution. Below I have outlined the extent of collaboration, with whom and under what auspices.

John Hellstrom (co-supervisor of this PhD thesis) and Petra Bajo from the University of Melbourne are acknowledged for training me and helping in the U-Th dating procedures presented in chapters 3 and 5. Russell Drysdale, also from the University of Melbourne, is acknowledged for training me in the art of IR-MS stable isotopes analyses presented in chapter 5. Daryl Howard from the Australian Synchrotron (Melbourne) contributed to the data acquisition of SR-µXRF analyses presented in chapter 3. Gerda Gloy from the Bruker Nano Analytics (Brisbane) helped with the µXRF analyses presented in chapter 3. Floriana Salvemini from Australian Nuclear Science and Technology Organisation – ANSTO, assisted at the neutron tomography experiment presented in chapter 4. Vladimir Luzin from ANSTO contributed to the acquisition and processing of neutron diffraction data presented in chapter 4. Jitendra Mata from ANSTO assisted with the small angle neutron scattering analysis and data processing presented in chapter 4. Sandro Montanari from the Osservatorio Geologico di Coldigioco assisted during the fieldwork at Frasassi cave and helped with the interpretation of the data.

Acknowledgement of Authorship

I hereby certify that the work embodied in this Thesis is my own work, conducted under normal supervision. I, Valentina Vanghi, was the primary investigator and lead author of all manuscripts presented in this Thesis.

------(Silvia Frisia) (Valentina Vanghi)

Dedicated to M3

Acknowledgements

This research project has been fully funded by the Australian Government within the Endeavour Award Postgraduate Scholarship program. I am therefore infinitely grateful to the Australian Government for giving me the opportunity to do a PhD and spend 4 wonderful years in this beau- tiful country that I now call home.

I also acknowledge the financial support, during the last two years of my PhD, through a Post- graduate Research Award from the Australian Institute of Nuclear Science and Engineering (AINSE).

My deepest and sincere gratitude goes to Silvia Frisia and Andrea Borsato my principal super- visors at the University of Newcastle, because during these four years I received a great super- efficient supervision and help every time I needed it. I felt always supported, encouraged and motivated and I have been working in a positive environment, which helped me a lot to get through all the typical ups and downs of a PhD. Thanks for having trusted me for this postgraduate project. A personal thanks for Silvia that, apart of being very competent in her job as professor and students supervisor, for me has been a friend and a point of reference. I should probably say an downunder-mum. Thanks for all the happy moments, the dinners at your place, our conversa- tion about life and Italy (I will never, never forgot your sincere and wise advices) and all the lunch-boxes you prepared many times for me. Andrea, un grazie personale also for all the laughs and funny moments shared together and especially, for all the speleo-adventures! I had so much fun mamma mia!

I am also very thankful to Russell Drysdale for all the (tons) of isotopes analyses I could do at his lab at the University of Melbourne, during these four years. Thanks Russ for being always so welcoming, friendly and helpful; I have always felt like one of your PhD student.

Thanks also to John Hellstrom (my co-supervisor) and Petra Bajo from the University of Mel- bourne for their help during the U-Th dating and for running the age-models.

I am also grateful for the support and supervision received at ANSTO from Floriana Salvemini, Jitendra Mata and Vladimir Luzin.

Thanks to Hugh Dunstan (University of Newcastle) who facilitated access to the fluorescence microscope.

Thanks also to Sandro Montanari from the Osservatorio Geologico di Coldigioco, Sandro Mar- iani, Nereo Preto for their support during the fieldtrips at Frasassi cave and for all the good moments spent together during the speleological campaigns.

Thanks to the Direnzione Regionale, the Soprintendenza Archeologica della Puglia and the municipality of Altamura for giving access and allowing sampling at Lamalunga cave. Thanks to the guys of the Centro Altamurano Ricerche Speleologiche (CARS) for assisting during the field work. Especially thanks to Giovanni Ragone for being very nice and welcoming with us.

I have to sincerely thanks all my uni colleagues. First of all Emma and Andrew, because they have been the first ones I met at Uni and they hold a special place inside my heart. I could not ask for better uni friends. Thanks for being so amazing with me and to have shared all the laughs and cries (many). I love you! ° Thanks to Caio for joking with me all the times, making me laugh and being my friend (and thanks for being so patient everytime I asked you questions about computer stuff) ° thanks to the beautiful, genuine and sweetest persons I know, Azadeh and Tina ° Thanks to Ebony for being a friend, for all the nice moments and talks we had and all the adventures we shared together ° Thanks to Loy for its politeness and kindness and for being a friend ° Thanks to my beautiful sweet friend Laura, it is always so nice to have you around uni ° Thanks to Hannah for all the wise advises and for being so nice to me all the time (you cooked lasagna for me once, I will never forget) ° Thanks to Judy and Danielle but also Hannah and Silvia again, for being such inspiring women in academia ° Thanks to Olivier pour être toujour tres gentil et simpa et pour parler en français avec moi parce que c’est tres important por moi.

Then I want to thanks my Newcastle multicultural family of friends, my best friends here. Thanks for your support and craziness and sorry if I behaved a bit like a weirdo in the past 3 or 4 months. Specifically, grazie al mio Sergione a cui voglio bene come ad un fratello e per il cibo provided in momenti di bisogno e no e per l’aiuto informatico ° gracias a Alicia y Alberto por llevar un poquito de España en Newcastle y gracias por animarme durante mis bajones ° Merci a ma amie française la plus belle du monde Clo, parce que je t’adore et tu sais ca ° Thanks to Elaine and Franci my fantastic austro-italian friends for all the good moments shared together, I am so glad I have met you, I feel a Pisano too ° Thanks to Tamara my running buddy and wonderful wise friend, thanks for being such a beautiful friend for me, you are my sunray ° Thanks to Melissa and Emily for all the quality moments shared and all the laughs ° Thanks to Heather and Svana for all the adventures we went together I miss you too so much ° Thanks to Angy e Andre for

all the good moments and for being always so positive and cheerful and radiant like the sun ° Than thanks to Kim, Larissa, Lyle, Amy, Tim, Pinky and many others that I have met here in Oz.

Thanks to all my beautiful flatmates (Elise, Craig, Vic, Naomi, Andy, Nick) thanks for being patient with me during the writing phase of my PhD. Thanks for sharing your life with me and making our house “home-sweet-home”.

Thanks to all my Uni Melbourne friends for considering me one of them and for hosting me at their places all the times I had to come to Melbourne. First of all, grazie to Michela (v.), because, now, you are like a sister for me and because you make me laugh like a crazy all the time we are together ° Thanks to ‘ompa Andre for all the cazzate che abbiamo combinato insieme and some of the most absurd situations we ended up in! Japan docet, ho detto tutto ° Thanks to Coralie because you are unique. Coralie is Coralie and I love you as you are ° Gracias a Arturo y Brenda para acogerme estupendamente en vuestra casa ° Thanks to Petra for being always so nice and patient with me, for all the things you thought me and your precious help

Now it is time to thank to all my Italian friends that even if so far away they always make me feel as if I am still living close to them and they still share their day-to-day life with me. However, I still miss you a lot. Un grazie speciale a Lola e Laura che sono le mie migliori amiche di una vita e nessuno potra’ prendere il vostro posto nel mio cuore. Grazie a Eu, Cosimo e Marias per essermi venuti a trovare a Newcastle e per avermi fatto rituffare nel passato. Grazie a Simo e l’Ali per le nostre skyppate ma veramente grazie a tutti voi per farmi ridere a crepapelle anche da lontano e farmi dimenticare le brutture (poche, per fortuna) della vita. Io senza tutti voi sarei persa. Grazie Marco, Fra, An e tanti altri. Infine grazie anche alla mia cugina-sorella Sofia perche’ ti voglio un bene dell’anima. A tutti gli altri miei cugini e zii, ai miei fratelli Jacopo, Matte e Baby per avermi fatto sentire sempre il calore della nostra bellissima e unita famiglia.

Grazie ad i miei genitori per il supporto che mi hanno sempre dimostrato e per “lasciarmi andare” ogni volta che ho voluto. Questa tesi la dedico a voi con tutto il mio cuore.

Quiero tambien dedicar esta tesi a M. porque aunque ya no sea parte de mi vida, para mi ha sido un modelo de vida y le debo mucho, porque siento que sin el no haria podido empezar todo esto. Merci pour tout, je ne t'oublierai jamais.

Abstract

Stalagmites are acclaimed accurate proxies of climate variability because they can be precisely dated with radiometric techniques and preserve in their chemical and physical properties records of changes at sub-annual to orbital scales. Over the past two decades, stalagmite records have been used to reconstruct global teleconnections and synchronicity of events. At the same time, traditional proxies applications have not advanced as much as the development of new proxies has. The main goal of this thesis has been to fill this gap, by advancing knowledge on the physical aspects of stalagmites and other cave secondary mineral deposits (speleothems) that can be then be directly linked to climate and environmental processes. This main goal has been accomplished by using both conventional optical petrography and innovative, non-conventional methods such as Synchrotron Radiation based micro-XRF (SR-µXRF) and Neutron scattering.

SR-µXRF has been demonstrated to be the most apt technique to complement petrography in the investigation of speleothems, which have been here considered for their association with a unique paleontological finding. In this thesis, a petrographic, morphologic and microstratigraphic study of some coralloid formations both directly and indirectly associated with the complete skeleton of an early man preserved in in Lamalunga cave (Southern Italy) is presented to prove the reliability of this as archive of palaeo-hydroclimate. The hypothesis pre- sented in this Thesis is that coralloids formation is linked to hydroaerosol generated by the frag- mentation of cave drip combined to enhanced apical evaporation. Thus, their sub-micrometre scale layers preserve records of alternating dry and wet periods. Because of the small scale of the microstratigraphic elements, only SR-µXRF could be used to obtain elemental mapping with the desired high spatial resolution. SR-µXRF maps support the genetic hypothesis here formulated, and demonstrates that the incorporation and distribution of trace element and organic material are related to fabric changes. The overarching conclusion of this investigation is that coralloids, de- spite their small size are one of the best tools we have to reconstruct the climate and environmental context of early in Southern Italy. This will contribute to consolidate and improve the link between speleothem science and and archaeology.

The absence of stalagmites in Lamalunga cave, which may prevent obtaining a long, continuous and exhaustive palaeoclimate record, has led to the exploration of possible analogue in a highly decorated cave at the same longitude in Central Italy. Stalagmites from Frasassi cave have then

been selected and studied because at both Frasassi and Lamalunga locations, modern precipita- tions have similar δ18O composition, a phenomenon that is here assumed to have been the same throughout the Quaternary. Modern rainfalls isotopic signal variations, in the Italian peninsula, do not show a longitudinal gradient along the Adriatic coast, where both Lamalunga and Frasassi are located. With the aim of producing a stable isotopic record for Frasassi cave that could be used to complement the palaeoclimate reconstruction from Lamalunga coralloids, the first and necessary foundation has been benchmarking on the petrography the geochemical record of Frasassi cave. This ultimately allowed to interpret the δ13C signal of Frasassi stalagmite as reflect- ing local/regional scale humid/arid cycles, which coincide well with changes in petrography. By contrast, the δ18O signal does not follow petrographic changes and it is here concluded that it does not reflect drip rate variability (infiltration). It is highly probable that the δ18O reflects a mixed signal that of water stored in the aquifer for a relatively long time, “homogenized” through the years, rather than the immediate response to recharge. The interpretation of Frasassi stalagmite record highlights that, as in Lamalunga coralloids, fabrics best identify an immediate response of the speleothem archive to hydrological changes.

Because of their importance, the analysis of speleothem fabrics has been pushed beyond the con- ventional microscopy and spectroscopy methods by employing for the first time neutron scatter- ing techniques. This can only been regarded as a pilot study within this Thesis, however the pre- liminary results are promising. The aim was to help recognizing features that may indicate path- ways of crystallization. Neutron diffraction data produced a compilation of different preferred orientations for various types of speleothems characterized by diverse fabrics, which hints at an internal organization characterized by various degrees of rotation of the units composing crystals most likely around a common c-axis. Additional information comes from the application of small- angle neutron scattering (SANS), on the same specimens, which reveals the presence of mass or surface fractals. Tentatively, this is ascribed at the presence of nanocrystals. Both results pave the way to a re-evaluation of speleothem crystallization and, thus, incorporation of geochemical data when non-classical pathways of nucleation and growth influenced speleothem capture of climate change.

TABLE OF CONTENTS LIST OF FIGURES ...... IV LIST OF TABLES ...... XI PUBLICATIONS ARISING FROM THIS THESIS ...... XII 1. INTRODUCTION ...... 1

1.1 BACKGROUND ...... 1 1.2 SPELEOTHEMS FORMATION...... 3 1.3 PETROGRAPHY OF SPELEOTHEMS ...... 5 1.3.1 Architecture of speleothems: Fabrics ...... 9 1.3.2 Speleothem architecture: Laminae ...... 12 1.4 SPELEOTHEM CHEMISTRY ...... 15 1.4.1 Stable isotope ratios ...... 16 1.4.2 Trace elements ...... 18 1.5 STUDY SITES ...... 19 1.5.1 Reasons behind the choice of these two sites ...... 21 1.5.2 Frasassi cave system: speleogenesis and significance for Earth’s history ...... 22 1.5.3 Lamalunga cave current research status ...... 25 1.6 THESIS AIMS AND OBJECTIVES ...... 26 1.7 THESIS STRUCTURE ...... 27 1.8 REFERENCES ...... 32 CHAPTER 2. GENESIS AND MICROSTRATIGRAPHY OF CALCITE CORALLOIDS ANALYSED BY HIGH RESOLUTION IMAGING AND PETROGRAPHY ...... 40

2.1 ABSTRACT ...... 40 2.2 INTRODUCTION ...... 41 2.3 GEOGRAPHIC SETTING AND CORALLOID OCCURRENCES IN LAMALUNGA CAVE...... 43 2.4 MATERIALS AND METHODS ...... 47 2.5 RESULTS AND DISCUSSION ...... 51 2.5.1 Microstratigraphy ...... 51 2.5.2 Mineralogy and petrography ...... 55 2.5.3 Mechanisms of coralloid formation at Lamalunga Cave ...... 57 2.5.4 “Aragonite conundrum” in Lamalunga coralloids ...... 59 2.5.5 Microstratigraphic evidences for Lamalunga coralloids formation ...... 60 2.5.6 Mechanisms of formation of Lamalunga coralloids and hydrological implications ...... 62 2.6 CONCLUSIONS ...... 65 2.7 REFERENCES ...... 67 CHAPTER 3. HIGH-RESOLUTION SYNCHROTRON XRF INVESTIGATION OF CALCITE CORALLOID SPELEOTHEMS: ELEMENTAL INCORPORATION AND THEIR POTENTIAL AS ENVIRONMENTAL ARCHIVES ...... 72

3.1 ABSTRACT ...... 72 3.2 INTRODUCTION ...... 73 3.3 GEOGRAPHIC CONTEXT ...... 74 3.4 MATERIALS AND METHODS ...... 76 3.4.1 Morphological and structural characteristics of the coralloids ...... 76 3.4.2 Water analyses...... 77 3.4.3 U-series dating ...... 78 3.4.4 Micro-XRF and SR micro-XRF ...... 78 3.4.5 Principal component analysis (PCA) ...... 79 3.5 RESULTS ...... 80 3.5.1 Water analyses...... 80 3.5.2 U-series dating ...... 80

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3.5.3 Petrography, internal structure and morphology of Lamalunga coralloids ...... 81 3.5.4 Greyscale values and fluorescence stimulated microscopy ...... 85 3.5.5 Distribution maps of trace elements: SR-micro-XRF and micro-XRF maps ...... 88 3.5.6 Elemental quantifications for micro-XRF ...... 90 3.6 DISCUSSION ...... 94 3.6.1 Mg and Sr behavior in Lamalunga coralloids ...... 95 3.6.2 Silicon concentration in Lamalunga coralloids and possible origin ...... 96 3.6.3 Uranium, Iron and Bromine concentration ...... 98 3.6.4 Incorporation and concentration of the elements ...... 99 3.6.5 Models of elements incorporation ...... 101 3.6.6 Humid phase (climatic) ...... 101 3.6.7 Dry phase (climatic) ...... 102 3.6.8 Non climatic episodes ...... 102 3.6.9 Greyscale values significance ...... 103 3.7 CONCLUSIONS ...... 104 3.8 REFERENCES ...... 106 CHAPTER 4. NEUTRON SCATTERING PILOT STUDY ON SPELEOTHEM FABRICS COMPLEMENTARY CHARACTERIZATION OR ADVANCE IN KNOWLEDGE OF SPELEOTHEM PROPERTIES? ...... 112

4.1 BACKGROUND ...... 112 4.2 A BRIEF INTRODUCTION TO NEUTRON SCIENCE ...... 114 4.3 BRIEF INTRODUCTION TO NEUTRON TOMOGRAPHY ...... 116 4.4 MATERIALS AND METHOD ...... 116 4.4.1 Textural analysis ...... 117 4.4.2 Porosity analysis ...... 118 4.5 RESULTS AND DISCUSSION...... 119 4.5.1 Speleothem textural analysis (KOWARI) ...... 119 4.5.2 Significance of textural analysis of speleothems ...... 121 4.5.3 Porosity analysis ...... 123 4.5.4 SANS scattering ...... 126 4.6 CONCLUSIONS ...... 130 4.7 REFERENCES ...... 132 CHAPTER 5. CLIMATE VARIABILITY ON THE ADRIATIC SEABOARD DURING THE LAST GLACIAL INCEPTION: THE FRASASSI CAVE CASE STUDY...... 135

5.1 ABSTRACT ...... 135 5.2 INTRODUCTION ...... 136 5.3 FIELD LOCATION AND SAMPLE ...... 139 5.4 METHODS...... 141 5.4.1 Petrographic and fluorescence microscopy ...... 141 5.4.2 U-Th dating and age model...... 142 5.4.3 Stable isotopes analysis ...... 143 5.5 RESULTS ...... 146 5.5.1 Microstratigraphy and petrology ...... 146 5.5.2 U-Th series results ...... 147 5.5.3 Stable C and O isotopes ratio ...... 149 5.5.4 Grey values ...... 150 5.6 DISCUSSION ...... 152 5.6.1 Environmental interpretation of calcite fabric and FR16 δ13C ...... 152 5.6.2 Moisture provenance and interpretation of Frasassi δ18O signal ...... 155 5.6.3 Regional climatic context of δ18O during the glacial inception ...... 157 5.6.4 Possible factors influencing Frasassi δ18O signal ...... 160 5.7 CONCLUSIONS ...... 162

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5.8 REFERENCES ...... 164 CHAPTER 6. CONCLUSIONS ...... 170 CHAPTER 7. FUTURE DIRECTIONS ...... 174 APPENDIX I SPELEOTHEM CHRONOLOGY FROM FRASASSI CAVE SYSTEM (CENTRAL ITALY): TIMING OF SPELEOGENESIS, UPLIFT RATE AND PALEAOCLIMATE EVOLUTION...... 179

I. AIM OF THE RESEARCH ...... 179 II. MATERIALS AND METHODS ...... 179 III. DISCUSSION ...... 179 Hypogenic processes ...... 179 Frasassi karstic levels ...... 181 Stalagmite growth rates vs δ18O global records: preliminary hypothesis ...... 184 IV. PRELIMINARY CONCLUSIVE REMARKS ...... 185 V. REFERENCES ...... 186 APPENDIX II COMPOSITE Δ13C AND PETROGRAPHIC 196-355 KA RECORD FROM FRASASSI CAVE (CENTRAL ITALY) STALAGMITES: INVESTIGATING DRIVERS OF CALCITE CARBON ISOTOPE SIGNALS ...... 187

I. INTRODUCTION: C ISOTOPE RATIO IN SPELEOTHEMS ...... 187 II. MATERIALS AND METHODS ...... 187 III. RESULTS ...... 188 IV. DISCUSSION ...... 191 Significance of δ13C changes in Frasassi record ...... 191 V. CONCLUSIONS ...... 191 VI. REFERENCES ...... 192

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List of Figures

Fig. 1.1 Transfer of the geochemical signal from the outside to speleothems growth lay- ers………………………………………………………………………………………………...5

Fig. 1.2 Step-kink-hole model with adsorbed ions shown in black. Refer to the text for more details. Picture taken from Morse and Arvidson (2002)……..……………………………………………………………………………………...6

Fig. 1.3 Different pathways to crystallization by particle attachment. The classical theory of nu- cleation (De Yoreo and Vekilov, 2003), only accounts for the monomer-by-monomer crystal growth. Sketch tak-en from De Yoreo et al. (2015)…………………………………………………………………………………………….7

Fig. 1.4 Plots of free energy change as a function of nucleus size as envisaged by the classical, one-step and nonclassical nucleation models with intermediate amorphous phase. Plots taken from Lee et al. (2016)…………………………………………………………………………………………….8

Fig. 1.5 Some of the most common fabrics observed in stalag- mites…………………………………………………………………………………………….12

Fig. 1.6 (A) Geographical locations of the cave sites object of this study: Frasassi cave and Lam- alunga cave. (B) Giustini et al. (2016) map of spatial distribution of δ18O (‰) of precipitations in Italy……………………………………………………………………………………………...20

Fig. 2.1 A) Location of Lamalunga Cave near Altamura (Southern Italy). B) Plan and schematic cross section of Lamalunga Cave. The orange dotted line represents the plan of the cross section. The locations of the samples here studied (ABS5 and ABS6) are also indicated. ABS3 coralloid, studied in Lari et al. (2015), was sampled in the same chamber of the “Altamura Man” skeleton. Coralloid speleothems are represented with small dots. The original entrance was a vertical shaft now completely filled by limestone debris. The actual entrance to the cave was artificially en- larged. C) View of the hill where the cave opens to the surface (black cross)…………………………………………………………………………………………….42

Fig. 2.2 Different types of coralloid speleothems from Lamalunga Cave. A) The Neanderthal skeleton almost completely coated by coralloids. B) Main gallery showing coralloids that are mostly concentrated on the floor and on the lower parts of the walls, while they are almost absent on the upper parts of the walls and on the ceiling. This boundary is indicated by a dotted black line; C) rounded nodular coralloids developed upwind (yellow arrows represent the direction of the air-flux) on a large stalagmite, D) cylindrical coralloids; E) rounded nodular coralloids; F) branched coralloids………...... 44

Fig. 2.3 Images of samples ABS5 and ABS6. A) Polished slabs; B) complete thin sections in PPL; C) complete thin sections in XPL; D) Schematic interpretation of the principal features observed in the samples. Some crystals boundaries and major margins defining groups of crystals with same c-axis orientation, are represented with thin blue and black lines respectively. Thick black lines visualise the boundaries between the main microstratigraphic growth phases. Orange lines indicate possible hiatuses identified by dissolution/corrosion features. The black arrow in ABS6 panel D, indicates crystals becoming wider moving from the central axis towards the flanks: from fiber-like Ce (Fb) crystals to Ce crystals. Red layers correspond to micritic layers rich in Fe-

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oxides. Green rectangles indicate the regions analysed with fluorescent light. In ABS6, organic- rich bands are coloured with different shades of brown depending on the intensity of fluorescence emitted: e.g. darker brown parts are the most fluorescent. On the left side of ABS5 are also indi- cated the U/Th ages with 2σ errors published in Lari et al. (2015). Fabric codes: Ce = columnar elongated; M = micrite; OM = organic-rich layer; Ms = microsparite. Abbreviations: Fls = flow- stone-like; Crl = coralloid; I. Crl = incipient coralloid……………………………………..45

Fig. 2.4 Coupled PPL (parallel polarizers) thin sections and fluorescence maps (2 wavelenghts combined) for ABS5 and ABS6. The corresponding fluorescence and greyvalues line scans were carried out along the dashed vertical lines. Fabrics and major discontinuities for the thin sections are labelled as follows: Ce = columnar elongated; M = micrite; OM = organic-rich layer; MS = microsparite. To facilitate their correlation of greyscale values and fluorescence intensity, diverse fabrics have been highlighted by diverse coloured bands. Blue has two different shades, dark and light, which are intended to reflect higher (++) or lower (+) concentration of organic material (OM) and higher (ff) or lower (f) fluorescence intensity respectively. The presence of clean, com- pact Ce calcite parts is illustrated as white bands. Hiatuses are marked by black (clearly recog- nizable gap) and blue (possible gap) dotted lines. Note that the fluorescence intensity scales are inverted………………………………………………………………………………………….48

Fig. 2.5 A) Ensemble of cylindrical coralloid growing on a bedrock fragment collected from the cave floor. The location of sample ABS6 is marked by a white box; Coralloids speleothems can assume many different shapes and forms and their internal structure is commonly highly lami- nated: B) Cylindrical coralloid with incipient branching termination; C) complex globular coral- loid; D) Cone-shaped coralloid which was growing on the Neanderthal skeleton (Lari et al., 2015)………………………………………………………………………………...…………..49

Fig. 2.6 Discontinuities and hiatuses observed in PPL. A) Dark levels in ABS5 formed by four different hiatuses. B) Detail of A) (red rectangle). The flat terminations of some crystals have been corroded with micrite filling the voids (yellow arrow). C) Detail of B) (red rectangle). D) and E) Hiatuses in ABS5 with micritic veils capping the crystals terminations, showing corroded surfaces (blue arrows). F) Finely laminated axial part in ABS6. The darker laminae are due to the presence of micrite and organic-rich particles. G) Detail of F) (red rectangle) showing a corroded surface where, on top, another level of crystals with spherulitic growth started nucleating. H) Irregular micrite layer at the base of ABS6. The red colour is caused by the presence of iron oxides. Scale bars correspond to 0.5 mm for A) and F), to 100 µm for B), C), D), E), H), and G)………………………………………………………………………..………………………52

Fig. 2.7 Thin sections photos taken under PPL (A, C, E) and XPL (B, D, F). A) and B): columnar elongated fabric (Ce) in ABS5. Dark micritic and organich rich layers interrupt the growth of the crystals. C) and D) ABS6 fiber-like crystals with evidence of spherulitic-type growth. The lamina couplets are formed by micrite (M) and organic rich dark layers alternating with clean compact calcite layers. E) ABS6 acute crystal terminations, which suggest a relatively thick film of fluid; and F) ABS6 flat crystal tips and some possible eroded surfaces capped by a dark material con- ceivably containing organic matter (see text for details). Scale bars are 0.5 mm for A) and B) and 100 µm for C), D), E) and F)………………………………………………………………………………………………...53

Fig. 2.8 A) Sketch representing the processes involved in the formation of coralloid speleothems in Lamalunga cave. When a drop hits a surface inside the cave, it splits in smaller droplets which then bounce and spread in the surrounding. If an air flux (blue arrows) is present inside the cave, hydroaerosol is produced downwind. B) Sketch representing the mechanisms controlling the for- mation of lenticular dark bands and white isopachous bands. When the concretion is fed by hy- droaerosol the water supply is limited (Case 1). Long periods of evaporation (red arrows), helped

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by ventilation (indicated by blue arrows), is the principal mechanism controlling the growth of a coralloid. Also the transport of impurities (colloids) by hydroaerosols which get preferentially deposited on the tips, promotes coralloid type of growth by inducing the nucleation of fiber-like crystals of calcite. When, instead, the water supply is relatively higher because is mostly derived by splashing drops and evaporation is reduced, impurities (colloids) are diluted and clean elon- gated columnar calcite forms (Case 2)……………………………………………………………………………………………….. 55

Fig. 2.9 Sketch illustrating factors controlling Lamalunga coralloids evolution. Arrowed bars il- lustrate graphically the concept of increasing importance of each factors on the evolution of cor- alloids morphology. For example, branched and cylindrical coralloids are the result of the com- bined action of hydroaerosol feeding and evaporation driving to supersaturation with respect to calcite. In addition, branching coralloids likely form when the amount of impurities reaching the growing surfaces is maximum. Impurities, likely carried by hydroaerosols, are preferentially de- posited on the convex surfaces and seem to control the growth of fiber-like crystals and their elongation in the direction of growth. Relatively stronger evaporative processes on the protruded parts of the concretion forester the nucleation of fiber-like crystals which tend to grow faster compared to the crystals on the flanks of the coralloid. The flowstone-like morphologies are di- rectly fed by spray produced by nearby drops splashing thus forming a water film on the top of the speleothem. Because of the smoother morphology, flowstones-like coralloid formation is here inferred to be driven by relatively more intense CO2 degassing and lower evaporation than their branching and cylindrical counterparts. Furthermore, a relatively more constant water supply and reduced impurities input at the top would promote growth of elongated columnar crys- tals…………………………………………………………………………………………..…...61

Fig. 3.1 A) Map of Italy with the location of Lamalunga Cave near Altamura. B) Plan and sche- matic cross section of Lamalunga Cave. The orange dotted line represents the plan of the cross section. The locations of the samples here studied (ABS5 and ABS6) are also indicated. ABS3 coralloid, studied in Lari et al. (2015), was sampled in the same chamber of the “Altamura Man” skeleton. Coralloid speleothems are represented with small dots. A vertical shaft completely filled by limestone debris clogs the alleged original entrance. The actual entrance to the cave was arti- ficially enlarged. C) View of the hill where the cave opens to the surface (black cross)………………………………………………………………………………….…………73

Fig. 3.2 Polished slabs of the investigated coralloid samples. A) ABS6-A, B and C are part of the same multiaggregate of coralloids. The corresponding planes of cut are also shown (white rectan- gles). Notice the different plane of cut for ABS6-C that is orthogonal to the other two. B) ABS5 slab. The sample was growing on a broken stalag- mite……………………………………………………………………………….……………..75

Fig. 3.3 Synchrotron elemental (Ca, Sr,) concentrations plotted against grey values intensities from the polarised thin section and the fluorescence map (using 2 wavelenghts, blue and green, combined) for ABS5 and ABS6-A. The corresponding fluorescence and greyvalues line scans were carried out along the dashed vertical lines. Fabrics and major discontinuities for the thin sections are labelled as follows: Ce = columnar elongated; M = micrite; OM = organic-rich layer; MS = microsparite. To facilitate their correlation of greyscale values and fluorescence intensity, different fabrics have been highlighted by diverse coloured bands. Blue has two different shades, dark and light, which are intended to reflect higher (++) or lower (+) concentration of organic material (OM) and higher (ff) or lower (f) fluorescence intensity respectively. The presence of clean, compact Ce calcite parts is illustrated as white bands. Hiatuses are marked by solid blue (clearly recognizable gap) lines. Note that the transmittance intensity and Ca scales are in- verted…………………………………………………………………………...……………..80

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Fig. 3.4 SR micro-XRF maps (Ca, Sr, Fe and elastic signal) of ABS5 compared to the correspond- ing image of the polished slab (A) and the petrographic thin section under polarized light (B). Note that the thin section was made 2 mm away from the slab plane and thus it shows a slightly different architecture. Sr and Fe are preferentially concentrated along the dark micritic-rich bands on the thin section corresponding to the opaque milky bands on the slab. This corroded surfaces represent moment of no calcite deposition (hiatuses) indicated by Ht A, B and C. The ages (ka) published in Lari et al. 2015 are indicated in (A). Scale bars unit is in ppm for the elements maps and in percentages for the elastic scatter map……………………………………………………………………………………………...81

Fig. 3.5 A) Synchrotron distribution map (Ca and Sr) of thin section ABS6-A compared to the polished slab (a) and to the thin section under parallel polarizers (PPL) (b). Sr concentrates pref- erentially in the axial part of lenticular-shaped bands that appears opaque on the slab (a) and dark in the thin section (b). Where the growth band is more isopachous, Sr concentration is lower. Sr- rich layers are also present above hiatuses (Ht A, B and C) identified by clear dissolution features (arrows). The three U-Th ages (expressed in ka) are also indicated. Scale bar unit is in ppm. B) Zoom-in of the region indicated by a white rectangle in (A). Parallel (PPL) and crossed polarized (XPL) micrographs compared to Ca and Sr SR micro-XRF maps of the laminated part in ABS6- B. Dark regions in the thin section corresponds to low values for Ca, thus reflecting a relatively high intercrystalline porosity. Translucent parts are instead very dense as shown by high Ca val- ues. Black circles confine regions with low Ca concentration which in some cases are rich in Sr, when also Sr is low they represent voids possibly filled by other elements (white ar- rows)………………………………………………………………………….…………………82

Fig. 3.6 Synchrotron micro-XRF elemental maps of ABS6-B compared to the corresponding pol- ished slab (A). The elements concentrate mostly where Ca concentration is low and where the laminae appear white under natural light. Sr and Br tend to be more concentrated in lenticular shaped stacks of layers. Fe and Y mostly are concentrate at the base of the coralloid where micrite layers have been observed. U concentration pattern is similar to Sr distribution. Principal hiatuses (Ht A, B and C), are marked by white arrows.. The three U-Th ages (expressed in ka) are also indicated. Scale bars unit is in ppm for the elements maps and in percentages for the elastic scatter map……………………………………………………………………………..……………….84

Fig. 3.7 Synchrotron elements (Ca, Sr, U, Br, Fe and Mn) distribution maps of ABS6-C compared to image of the polished slab (A) and to the micro-XRF intensity images (squared maps on the left side) (Ca, Si, P, Mg and Sr). The tracers mostly concentrate where Ca concentration is low and where the laminae show a white coloration on the slab. The black rectangle on the slab shows the position of the micro-XRF maps. The small yellow rectangle show the region from where elemental concentrations have been quantified. Principal hiatuses (Ht A, B and C), are marked by white arrows. Scale bars unit is in ppm………………………..…………………………………………………………………….85

Fig. 3.8 A) Element distribution maps obtained with the conventional micro-XRF for Mg, Si and Ca in a small region of ABS6-C (yellow insert in figure 3.7). Si has opposite pattern of distribution with respect to Ca and is the element with the higher concentration after Ca. In the opaque bands Si is very high, up to 16% and Mg can reach up to 3%. In compact translucent bands, Si is very low (~ 0.1 %) whereas Mg is around 0.4%. B) Line scans of Ca, Si, Sr and Mg extracted in the central part of the maps (black rectangle) by geometrically interpolating the pixels. Sr and Mg trends show a similar pattern of distribution. Si seems mostly concentrated in grains with a 50- 100 µm diameter……………………………………………………………………………..….87

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Fig. 3.9 Sr concentration along selected growth layers in ABS6-B. The Sr concentration was measured along the seven 100µm width bands visualised by dashed red lines on the Sr map (black/white scale where white represents the max concentration of 2100 ppm and black the min- imum of 0 ppm). The graph on the right plots the Sr concentration along the bands centred on the coralloid growth axis. In band 4 the cycles in the central part have a period of 138 ±24 µm………………………………………………………………………………….……………89

Fig. 3.10 Principal component analysis (PCA) for ABS6-B (SR micro-XRF data) and ABS6-C (conventional micro-XRF data). Only PC1 and PC2 were compared in scatter plots because they show the most significant variances. The red circles enclose the elements with significant load- ings. GV = greyscale val- ues…………………………………………………………………...…………………………..90

Fig. 3.11 Linear correlations between Sr, Mg, Si and Ca in ABS6-C (micro-XRF data in Fig. 8) from a selected region of interest. The correlations were then calculated for the whole interval and then separately for the translucent (compact) and opaque (porous) calcite end-mem- bers………………………………………………………………………………………..…….91

Fig. 3.12 Schematic figure that shows all the principal characteristics of Lamalunga coral- loids……………………………………………………………………………...…………….102

Fig. 4.1 Idealised power law scattering curve showing Guinier, Transition and Porod regimes………………………………………………………………………………………...113

Fig. 4.2 Pole figures of speleothems from the neutron textural analyses carried out at the ANSTO KOWARI beamline. See text for the details.…………………………………………………………..……………………………...118

Fig. 4.3 Tensor view 3D representation of the porosity observed in a laminated portion of FR16…………………………………………………………………………………………...122

Fig. 4.4 Histograms of the different kinds of porosity in FR16 analysed by neutron tomography. For each fabric observed in FR16 (compact columnar, open columnar), two histograms have been created accordingly to the presence/absence of organic material and fluid inclusions. On the x- axes are reported volumes ranges of the pores in microns squared……………………………………………………..…………………………………..123

Fig. 4.5 Cross-section of scattering intensity (= neutrons counts on the area of the detector) (I) vs. scattering vector Q. Q = 4π sin (θ)/λ. The scattering vector represents the distance between incident and scattered directions. Q=0 means no scattering of the neutron beam. Dots represent Frasassi samples scattering curves and the lines corresponds to CL9, CS10, MIK7 and TM19 scattering curves. For FR16 P indicates porous calcite, PP = very porous calcite, Tr = translucid calcite……………………………………………………………………………………..……126

Fig. 4.6 Sketch representing a surface and mass fractal and the typical cross section plot that they yeld (curve slope = 3). I is the scatter intensity and Q is the scatter vector (modified from Hammouda (2008))……………..……………………………………………………………...126

Fig. 4.7 FR16 samples cross-section having scattering intensity (= neutrons counts on the area of the detector) (I) vs. scattering vector Q after Power Law model fitting. Q = 4π sin (θ)/λ. The scattering vector represents the distance between incident and scattered directions. Q=0 means no scattering of the neutron beam. Note that curve fitting has to be improved at high and low Q. Black dots represent the Frasassi samples scattering data and the red line is the Porod curve after

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the fitting. P = porous calcite PP = very porous calcite; Tr = translucent calcite…………………………………………………………….…………………………….127

Fig. 4.8 Plot of scattering intensity (= neutrons counts on the area of the detector) vs. scattering vector Q after Power Law model fitting. Q = 4π sin (θ)/λ. The scattering vector represents the distance between incident and scattered directions. Q=0 means no scattering of the neutron beam. Black dots are the scattering data and the red line is the Porod slope after the fitting. Note that curve fitting has to be improved at high and low Q. CL9 is a flowstone from Collalto cave (Italy); CS10 is a dolostone from Costalta cave (Italy); MIK7 is a microbialite; TM19 is laminated stalagmite from Tam Doum Mai (Laos)…………………...……………………………………………………………………...127

Fig. 5.1 A) Geographical location of Frasassi cave system (red dot in the map of Italy). B) Map of Grotta Grande del Vento of Frasassi karstic system. C) Section of the western part of Grotta Grande del Vento (the plane of cut is indicated with the red dotted line in B) and location of where FR16 was collected (Manhattan chamber, V° karstic level). The altitudes of the karstic levels indicated in the section are calculated from the river bed. Map and section of the cave are simpli- fied versions from the original made by Dottori D., Maccio S., Bocchini A., Coltorti M., Novelli A. and Recchioni R. during the speleological campaigns from 1973 to 1985…………………………………………………………………………………………....135

Fig. 5.2 Geologic cross section of Frasassi anticline modified from Galdenzi et al. (2008b). Infiltration water and sulfuric exhalations are indicated by blue and green shaded arrows respectively. Normal and thurst fault lines are indicated by red arrows...... 136

Fig. 5.3 Principal fabrics observed in FR16 (photo in the centre of the figure): compact columnar (dark grey in the sketch of the stalagmite), open columnar (light grey), micrite and microsparite (yellow). On the right of the sketched stalagmite, the photos at parallel and crossed nicols of some of the thin sections. On the left micrographs of the principal fabrics observed under the optical microscope. The red arrow indicate the hiatus separating the micrite fabric to the columnar fabric. Red scale bars in the micrographs correspond to 1 mm. Thin sections short side measures 1.2 cm…………………………………………………………………………………………...…141

Fig. 5.4 FR16 stable isotope signal (d13C and d18O) compared to petrographic log (light orange line) and greyscale values (blue graph). C = compact columnar fabric; C/Co = laminated part where compact and open columnar fabric alternate; M/Ms alternation between micrite and micro- sparite fabric. “Hi” indicates the hiatus visually marked in the polished slab as a change from micrite to laminated fabric. The hiatus is also recorded by the abrupt shift in the isotopic profiles. The negative peaks are marked by red arrows and possibly indicate 5 cycles toward arid condi- tions……………………………………………………………………………………………142

Figure 5.5 Age-depth model for FR16 after A) and before B) the hiatus. Red dots represent the U-Th ages (see Table 1). Dark and light-grey lines represent 1σ and 2σ errors, respectively. The derived growth-rate time series C) and D) where grey lines represent the 2σ errors. Depths are measured from the top of the stalag- mite………………………………………………….…………………………………………146

Fig. 5.6 Comparison of δ13C and δ18O records from FR16 and stalagmite CC28 from Corchia Cave (Drysdale et al., 2007a) during MIS5c and MIS5d. The hiatus in FR16 is indicated with “Hi”. Numbers correspond to the phases of growth. Red arrows represent maximum positive δ13C peaks reflecting arid events. GS24 and GS25 cold stadials documented in Greenland ice core (NGRIP) are indicated in CC28 and shaded in yellow. Summer insolation at 43°N (Laskar et al.,

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2011) and FR16 ages with respective 2σ-uncertanties are also shown. The blue graph represents the reflectance of the stalagmite surface in greyscale values whereas the bold black line is FR16 growth rate……………………………………………………………………………………..148

Fig. 5.7 Analysis of the isotopic composition (oxygen and deuterium) of modern drip waters col- lected in Frasassi cave during the period 2014-2015, compared to the water lines of isotopic com- position of modern precipitation from all the Mediterranean region (Giustini et al., 2016b). The Italian meteoric water line is also showed as well as the local Sicilian water line………………………………………………………………………………………….….152

Fig. 5.8 Continuous wavelet analysis of FR16 δ18O and δ13C signals using the continuous wavelet transform toolbox for MATLAB (Grinsted et al., 2004). The isotopic time series are represented at the bottom of the power spectra. The thick black contour designates the 5% significance level against red noise and the cone of influence. The period time unit is in ka. The resulting periodicity varies between 1 to 4 ka like the DO events and are especially evident in the pre-hiatus phases of the stalagmite…………………………………………………………………………………..157

Fig. A1.1 Interpretation of the evolution of Frasassi system from an original, modified from an unpublished drawing by A. Mon- tanari………………………………………………………………………..………………….177

Fig. A1.2 H2S vapours chimney (photo on the left side). Gypsum deposit (photo on the right side)…………………………………………………………………………………………....178

Fig. A1.3 Uplift rate for the different karstic levels graph………………………………………………………………………………...…………179

Fig. A1.4 Age models and main fabrics observed for the sam- ples…………………………………………………………………………………….………180

Fig. A1.5 Growth rates of Frasassi stalagmites are compared with NGRIP ice core δ18O record and LR04 marine benthic δ18O record (Lisiecki and Raymo, 2005). Sapropel events and marine isotope stages (MIS) are also indi- cated……………………………………………………………………………..…………….182

Fig. A2.1 FR11 and FR12 grey scale profiles. High values (>110) correspond to the porous parts of the stalagmites characterized by open and/or porous columnar fabrics. Translucent zones are formed by compact calcite which is indicated by low grey values (<110)…………………………………………………………………………………….……186

Fig. A2.2 Frasassi δ13C record and grey values profile compared to LR04 marine benthic δ18O record (Lisiecki and Raymo, 2005), Antarctic atmospheric CO2 record (Petit, 1999) and summer insolation curve (Laskar et al., 2004). Marine isotope stages (MIS) 7 to 10 and terminations III and IV are also indicated. Blue dots represent the U-Th dates performed on FR11 and FR12 with 2σ error bars. Green boxes highlight interglacials and interstadi- als…………………………………………………………………………………..…………..187

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List of Tables

Table 1.1 Most common chemical proxies commonly used in speleothem science, for more de- tails please refer to the main text………………………………………………………………………………………………15

Table 3.1 Hydrochemical characteristics of the cave waters collected at Lamalunga cave in May 2008..……………………………………………………………………………………………78

Table 3.2 Results of Multicollector ICP Mass Spectrometry U/Th analyses on the coralloid ABS6-A and ABS5 (Lari et al. 2015). The isotope analyses are reported as activity ratios (AR), the errors are reported in brackets as ±2σ…………………………………………………………………………………………...….79

Table 3.3 Mean values in translucent (Trans) and opaque calcite fabric expressed in mg/g ±1σ for selected intervals in coralloid samples ABS6-B, C (cf. Fig. 3.7) and ABS5 (cf. Fig. 3.4) meas- ured in conventional µXRF and with SR- µXRF………………………………………………………………………………………..….88

Table 4.1 Power law slope parameters (m) for the analysed carbonate samples……………………………………………………………………………..………….124

Table 5.1 Results of Multicollector ICP Mass Spectrometry U-Th analyses on calcites. The iso- tope analyses are reported as activity ratios (AR), and the errors are reported in brackets as ±2σ. The black bold line indicates the position of the hia- tus………………………………………………………………………..…………………….145

Table 6.1 List of all the samples collected in Frasassi cave and corresponding time span of growth……………………………………………………………………………………….…172

Table A1 Uplift rate of the different karst lev- els…………………………………………………………………………………..…………..179

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Publications arising from this thesis

Peer-reviewed Publications

Vanghi, V., Frisia, S., Borsato, A. 2017. Genesis and microstratigraphy of calcite coralloids ana- lysed by high resolution imaging and petrography. Sedimentary Geology 359, 16-28.

Vanghi, V., Borsato, A., Frisia, S., Howard, D. L., Gloy, G., Hellstrom, J., Bajo, P. High-reso- lution synchrotron XRF investigation of calcite coralloid speleothems: elemental incorporation and their potential as environmental archives. Submitted. Sedimentology.

Vanghi, V., Frisia, S., Borsato, A., Hellstrom, J., Bajo, P. Climate variability on the Adriatic sea- board during the last glacial inception: the Frasassi cave case. Accepted. Quaternary Science Re- views.

Conference Proceedings

2016 American Geophysical Union (AGU) Fall meeting San Francisco (USA). Vanghi et al. Composite δ13C and petrographic 195-355 ka record from Frasassi cave (central Italy) stalag- mites: investigating drivers of calcite carbon isotope signals.

2015 International Union of Quaternary Research (INQUA) XIX conferences, Nagoya (Japan). Poster presentation: Vanghi et al. Speleothem chronology from Frasassi cave system (Central Italy): timing of speleogenesis, uplift rate and paleaoclimate evolution.

2014 Climate Change: The Karst Record VII (K7) conference, Melbourne (Australia). Poster presentation: Vanghi et al. Coralloid speleothems associated with Neanderthal skeleton in Altamura cave (Southern Italy): environmental constrain and paleoclimate significance.

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