marine bivalve records of antarctic seasonality and biological responses to environmental change

390 Pages·2017·21.19 MB·English

MARINE BIVALVE RECORDS OF
ANTARCTIC SEASONALITY AND BIOLOGICAL
RESPONSES TO ENVIRONMENTAL CHANGE
OVER THE CRETACEOUS-PALEOGENE MASS
EXTINCTION INTERVAL

Joanna Louise Ong Hall

Submitted in accordance with the requirements for the degree of
Doctor of Philosophy

The University of Leeds

School of Earth and Environment

December 2017
The candidate confirms that the work submitted is her own, except where work
which has formed part of jointly authored publications has been included.

The contribution of the candidate and the other authors to this work has been
explicitly indicated below. The candidate confirms that appropriate credit has
been given within the thesis where reference has been made to the work of others.

The work in Chapter 6 of the thesis has been accepted for publication pending
revision as follows:
Hall, J.L.O.; Newton, R.J.; Witts, J.D.; Francis, J.E.; Hunter, S.J.; Jamieson,
R.A.; Harper, E.M.; Crame, J.A.; Haywood, A.M.
Sulfate and seasonality: Extreme methane signals in Late Cretaceous Antarctic
bivalves
In revision for Earth and Planetary Science Letters
The candidate is the lead author and is responsible for all data analysis,
interpretation and for writing the manuscript. Fieldwork and fossil sampling in
Antarctica was conducted by Francis and Crame. Witts and Jamieson provided
additional isotope data from sediments and bulk bivalves for comparison. Hunter
assisted with hydrate modelling. All co-authors provided intellectual input and
editorial changes to the draft manuscript.

This copy has been supplied on the understanding that it is copyright material
and that no quotation from the thesis may be published without proper
acknowledgement

The right of Joanna Louise Ong Hall to be identified as author of this work has
been asserted by her in accordance with the Copyright, Designs and Patents Act
1988.
ABSTRACT

The Cretaceous-Paleogene mass extinction event occurred 66 million years ago
and had a profound effect on the course of evolutionary history, with the
extinction of up to 75% of life and larger effects on the broader Earth system. A
number of studies posit that the severity of this extinction event may have been
amplified by climate variability and destabilisation in the latest Cretaceous –
immediately prior to the extinction event. The strong seasonal forcing in the
polar high latitudes is likely to have enhanced any such effects during this time
period; additionally, the historical mismatch between late Cretaceous proxy data
and climate simulations is particularly pronounced at high latitudes and both
the effects of a stronger seasonal cycle on proxy temperature conversions, and
misrepresentation of seasonality in climate models have been suggested as factors
in the mismatch. This makes the Antarctic an extremely valuable location to
study with regards to seasonality from a proxy- and model- based perspective.
Seymour Island is a rare and valuable Antarctic K-Pg boundary site with a good
framework of fossil, stratigraphic and sedimentological study, which makes fossil
material ideal for investigation of the effects and impacts of seasonality and
environmental change across the mass extinction interval.

This thesis presents a detailed study focusing on using fossil bivalve shell material
from the Seymour Island section to reconstruct records of Antarctic climate and
seasonality across the K-Pg mass extinction event. New data were obtained
about the seasonal growth patterns of these bivalves to understand their growth
and ontogenetic response to potential climate variability and the effects of the
mass extinction. For the first time, sub-annual resolution stable carbon and
oxygen isotopic data were produced from Seymour Island’s bivalve shells to show
seasonal changes in temperatures and detect changes in biogeochemical cycling
and methane influence through the section. These data were integrated with a
series of oxygen isotope enabled climate simulations to address potential issues
converting from isotopic to temperature data in a highly seasonal environment
and provide further information regarding the influence of sea ice. Combining
new proxy- and model- based knowledge in a series of sensitivity experiments, it
was shown that both sets of data display good agreement under realistic sets of
parameters, suggesting that seasonality was important for the development of
polar ecosystems. Warm summer temperatures may have been key in permitting
the ecological strategy in these bivalves of slow growth to large sizes, which in
turn may have contributed to survivorship across the K-Pg boundary.

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ACKNOWLEDGMENTS

Firstly, I would like to thank my many supervisors, Alan Haywood, Rob Newton,
Jane Francis, Liz Harper, Alistair Crame and Steve Hunter for all of their
guidance, enthusiasm and encouragement over the course of this project. Thank
you for lending me some of your scientific knowledge and for your patience
whenever I was unable to see the way forward. I am also grateful to the Natural
Environment Research Council for financial support to allow this research, and
the British Antarctic Survey for their CASE funding.

I would also like to thank Rowan Whittle and the PalaeoPOLAR Research
Group for helping to put everything Seymour Island into context and Cris Little,
Christian Marz, Ben Mills and members of the Palaeo@Leeds Group for useful
scientific discussions over Friday fish and chips throughout my time at Leeds.
To everybody I've shared an office with; James, Laura, Tom, Rhian, Autumn,
Carl, Adam and the various office pets. Thank you for many years of your
advice, support and distractions.

Thanks go to my friends outside of Leeds as well as everybody I have gamed,
travelled and sparkled with along the way. Thank you for providing so many
wonderful spaces to escape to and reminding me that I am lucky to have been
able to work on this project for the past four years. Special mentions go to
Rhiannon for giving me so many remedial grammar lessons without complaint,
and to Luke for fixing both my maths and my brain every time I broke them.

Finally, I would like to thank my parents, Mike and Chew-Lan for always trying
to understand and not letting me give up and my brother, Jonny for somehow
being able to say, "do it" exactly once to push me through any mental block:
I'm glad you use your powers for good and not evil. None of this would have
been possible without all of you.

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CONTENTS

List of Tables ............................................................................................... vii
List of Figures ............................................................................................... ix

1: Introduction ............................................................................................... 1
1.1 Introduction ...................................................................................... 1
1.2 Aims and Objectives ......................................................................... 6
1.3 References ......................................................................................... 7

2: Geological Setting .................................................................................... 14
2.1 Introduction .................................................................................... 14
2.2 Regional Tectonics and Palaeogeography ....................................... 14
2.3 General Stratigraphy of the James Ross Basin .............................. 18
2.3.1 Gustav Group .......................................................................... 21
2.3.2 Marambio Group ..................................................................... 21
2.3.3 Seymour Island Group ............................................................ 22
2.4 Stratigraphy and Palaeoenvironments of Seymour Island.............. 23
2.4.1 Haslum Crag Member ............................................................. 25
2.4.2 López de Bertodano Formation .............................................. 25
2.4.3 Sobral Formation .................................................................... 29
2.4.4 Cross Valley Formation .......................................................... 30
7.1.1 La Meseta Formation .............................................................. 31
2.5 Palaeoclimate Records .................................................................... 32
2.5.1 Antarctic Marine Records ....................................................... 33
2.5.2 Antarctic Terrestrial Records ................................................. 34
2.6 Specimen Collection ........................................................................ 36
2.6.1 Stratigraphic Nomenclature .................................................... 38
2.6.2 Collection Bias ........................................................................ 41
2.7 Specimen Preservation .................................................................... 42
2.8 Summary ......................................................................................... 46
2.9 References ....................................................................................... 47

3: Growth Patterns and Longevity .............................................................. 59
3.1 Introduction .................................................................................... 59
3.2 Objectives ....................................................................................... 61
3.3 Rationale of Taxon Choice ............................................................. 61
3.4 Seasonality of Growth ..................................................................... 64
3.4.1 Methods ................................................................................... 65

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3.4.2 Results ..................................................................................... 68
3.4.3 Discussion ................................................................................ 72
3.5 Morphometrics ................................................................................ 74
3.5.1 Methods ................................................................................... 74
3.5.2 Results: Ontogeny and Allometry ........................................... 74
3.5.3 Discussion: Ontogeny and Allometry ...................................... 82
3.5.4 Results: Size changes through stratigraphy ............................ 83
3.5.5 Discussion: Size Changes Through Stratigraphy .................... 88
3.6 Growth Rates and Longevity .......................................................... 89
3.6.1 Methods ................................................................................... 89
3.6.2 Results ..................................................................................... 90
3.6.3 Discussion ................................................................................ 93
3.7 Discussion ....................................................................................... 95
3.7.1 Morphometric Changes at the K-Pg Boundary ...................... 95
3.7.2 Size Distribution Changes at the K-Pg Boundary ................ 100
3.7.3 Growth Rate and Longevity ................................................. 107
3.8 Summary ....................................................................................... 113
3.9 References ..................................................................................... 114

4: Climate of the James Ross Basin........................................................... 122
4.1 Introduction .................................................................................. 122
4.2 Objectives ..................................................................................... 123
4.3 Background to Techniques ........................................................... 124
4.3.1 Stable Oxygen Isotope Geochemistry ................................... 124
4.3.2 Clumped Isotope Geochemistry ............................................ 128
4.3.3 Computer Models .................................................................. 131
4.4 Methods ........................................................................................ 138
4.4.1 Stable Isotopes ...................................................................... 138
4.4.2 Clumped Isotopes .................................................................. 139
4.4.3 Climate Simulations .............................................................. 142
4.5 Results .......................................................................................... 146
4.5.1 Oxygen Isotope Data............................................................. 146
4.5.2 Clumped Isotope Data .......................................................... 151
4.5.3 Model Results ........................................................................ 154
4.6 Discussion ..................................................................................... 160
4.6.1 Proxy conversions and assumptions ...................................... 160
4.6.2 Maastrichtian climate conditions .......................................... 165
4.6.3 Data and Model Comparisons ............................................... 169
4.6.4 Evidence for Sea Ice .............................................................. 171
4.7 Summary ....................................................................................... 175

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4.8 References ..................................................................................... 177

5: Regional Temperature Seasonality and Variability ............................... 188
5.1 Introduction .................................................................................. 188
5.2 Objectives ..................................................................................... 190
5.3 Seasonality around Seymour Island .............................................. 190
5.3.1 Methods ................................................................................. 191
5.3.2 Results ................................................................................... 192
5.3.3 Discussion .............................................................................. 194
5.4 Climate Variability ....................................................................... 197
5.4.1 Methods ................................................................................. 198
5.4.2 Results ................................................................................... 199
5.4.3 Discussion .............................................................................. 203
5.5 Data Model Comparisons ............................................................. 204
5.6 Summary ....................................................................................... 212
5.7 References ..................................................................................... 213

6: Sulfate and Seasonality: Biogeochemical Cycles ................................. 218
6.1 Abstract ....................................................................................... 218
6.2 Introduction ................................................................................. 219
6.3 Methods ....................................................................................... 221
6.3.1 Stable Isotopic Analysis ...................................................... 221
6.3.2 Sedimentary Analysis ........................................................... 222
6.4 Results........................................................................................ 222
6.5 Discussion................................................................................... 228
6.5.1 Origins of the Shell Carbonate ±13C Signal ......................... 228
6.5.2 Extreme Seasonality in bottom water DIC-±13C .................. 232
6.5.3 Contribution of methane to bottom water DIC .................. 234
6.6 Conclusions ................................................................................ 237
6.7 References .................................................................................. 238

7: Discussion ............................................................................................... 245
7.1 Climate and Palaeoenvironment of the James Ross Basin ........... 246
7.1.1 Evidence for Seasonal Bias .................................................... 246
7.1.1 Mean State Climate Conditions ............................................ 246
7.1.2 Evidence for Climate Variability and Seasonality: ............... 252
7.2 Biogeochemical Cycling ................................................................ 254
7.3 Global Climate Context ................................................................ 257
7.3.1 Records of Global Temperature and Seasonality .................. 258
7.3.2 HadCM3L Simulations of Global Temperatures ................... 260

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7.3.3 Evidence for Seasonal Ice ...................................................... 263
7.3.4 The Influence of Atmospheric CO ....................................... 264
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7.4 Bivalve Responses to Environmental Effects ................................ 267
7.4.1 Size Changes.......................................................................... 268
7.4.2 Population Distribution and Bimodality .............................. 271
7.4.3 Productivity and Food Supply after the K-Pg ..................... 274
7.4.4 Redox and Oxygen Availability ............................................ 275
7.4.5 Overall Growth Strategy ....................................................... 276
7.5 Conclusions ................................................................................... 277
7.6 References ..................................................................................... 280

APPENDIX A............................................................................................ 292
APPENDIX B ............................................................................................ 295
APPENDIX C ............................................................................................ 341
APPENDIX D ........................................................................................... 350

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LIST OF TABLES

Table 2.1: Specimens have been referred to by number throughout this work.
These numbers correspond to the different field seasons and section
locations and collection types. Lists of specimens used for specific
geochemical, preservation or morphometric tests are available in Appendix
A. .............................................................................................................. 38
Table 2.2: XRD Results from sampled shell layers. The periostracal layers and
samples from the whole shell including surface contained the highest
percentage calcite. All other samples from the top 1 mm of shells contained
less than 3% calcite and the remainder aragonite. .................................. 44
Table 3.1: Isometry tests for bivalve specimens from the López de Bertodano
Formation ................................................................................................. 81
Table 3.2: Welch’s t-test results comparing major axis dimensions in shells from
the Cretaceous and Paleogene López de Bertodano Formation. This test is
to investigate whether the difference in box plots along the right-hand
columns of Figure 3.21-Figure 3.23 are likely to have been produced by
statistically different distributions at the 95% confidence level .............. 99
Table 3.3: P-Value from Shapiro Wilk Test for Normality. Bold values indicate
shell length data are not likely to be from a normally distributed
population .............................................................................................. 100
Table 3.4: HDS Value from Hartigan's Dip Test for Bimodality. Bold values
indicate shell length data show significant bimodality .......................... 101
Table 3.5: Summary table of size changes across the K-Pg boundary from the
Maastrichtian to Danian López de Bertodano Formation ..................... 106
Table 4.1: List of model parameter combinations used in this study with
designated names and the model outputs produced. ............................. 146
Table 4.2: ±18O data from microsampled shells showing the mean ±18O, winter
average ±18O calculated from the average of ±18O at each growth line,
summer average temperature calculated from the average of peak summer
±18O during each subsequent growth year increment (Y1-Y7) .............. 150
Table 4.3: Average oxygen isotopic composition of shells used for clumped
isotopic analysis temperature by species and stratigraphy (data from
Petersen et al. (2016) and Larkin (2014). Average ±18O is variable
sw

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between species, but appears to become more negative from the
Maastrichtian to the Danian. ................................................................. 153
Table 4.4: Seasonal temperature data from bivalve specimens sampled at high
resolution calculated from ±18O using two variations of conversion equation
to produce a “maximum” and “minimum” temperature estimate under a
range of potential water ±18O conditions ................................................ 163
Table 7.1: Biological mechanisms that can produce bimodality annotated with
tick and cross marks indicating whether each mechanism is likely to apply
to Lahillia or Cucullaea in this study. Modified from Huston & DeAngelis
(1987). .................................................................................................... 272

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