Late Cretaceous turmoil in the southern high latitudes: a story of environmental stress, basin restriction and  deltaic sedimentation from IODP Site U1512, Bight Basin, Australia

Carmine C. Wainman1 and Peter J. McCabe1

1Australian School of Petroleum and Energy Resources, University of Adelaide, Adelaide, Australia

The Bight Basin is a relatively poorly explored basin that developed during the break-up of Australia and Antarctica. The basin hosts a 15 km thick deltaic succession deposited during the height of the Cretaceous Greenhouse. Although there have been extensive seismic investigations and a few provenance studies from cuttings in the region, there is little well data and core material to undertake detailed investigations through this sequence. At Site U1512 offshore of southern Australia, IODP Expedition 369 recovered a 690 m thick succession of lower Turonian to upper Santonian silty claystone with only a few thin beds of glauconitic and sideritic sandstone (<32 cm thick). This core provides the most comprehensive record of depositional and paleoenvironmental events obtained from the Bight Basin. Clay-rich sedimentary facies and a dominance of agglutinated benthic foraminifera suggest the succession was rapidly deposited by hyperpycnal and hypopycnal flows in a marine prodelta setting, presumably in response to high terrestrial runoff. Organic geochemical and palynofacies data indicate sustained fluvial input into the basin with increases in delivery of plant-derived material. Marine-algal input slowly increases from the Turonian into the Santonian as indicated from C27/C29 steranes ratios between 1 and 1.5. Pristane/phytane ratios (1.73 to 0.13) in conjunction with common glauconite and pyrite reveal the basin became more dysoxic and restricted during Turonian and Coniacian times before slowly opening up during the Santonian. This was possibly due to the combined effect of a eustatic lowstand during the late Turonian, unstable patterns in oceanic circulation and increasing continental influence. Provenance studies from analysis of detrital zircons from the Coniacian part of the succession show that sediment was derived from similar sources determined for the Santonian to Maastrichtian succession in the nearby Gnarlyknots 1A well. Sediment was not only derived from the Whitsunday Large Igneous Province (~125–95 Ma) and the New England Fold Belt (~300–200 Ma) to the northeast, but also from the Albany-Fraser Orogen (~1.3–1.0 Ga) to the west. The gradual switch in sedimentary provenance during the Late Cretaceous was likely related to exhumation and erosion of these regions during the rifting of Zealandia off southeastern Gondwana. Evidence from Site U1512 suggests the basin was fed by two or more large transcontinental rivers that entered the restricted basin that were present before the break-up of Australia and Antarctica. These records offer a new understanding of Gondwanan paleogeography and our understanding of marginal marine settings in the southern high latitudes during the Cretaceous Greenhouse.


I am a Visiting Research Fellow at the University of Adelaide. I completed my PhD at the same university and received an MSci in Geology from the University of Southampton. My research focuses on Permian and Jurassic coal-bearing strata in Australia, and the Mesozoic evolution of Australia’s southern margin.

A microbial mayhem in the Chicxulub crater

Schaefer, Bettina1, Grice, Kliti1, Coolen, Marco J.L.1, Summons, Roger E.2, Cui, Xingqian2, Bauersachs, Thorsten3, Schwark, Lorenz3, Böttcher, Michael E.4,5,6, Bralower, Timothey, J.7, Lyons, Shelby, L.7, Freeman, Kate H.7, Cockell, Charles S.8, Gulick, Sean S.9, Morgan, Joanna V.10, Whalen, Michael T.11, Lowery, Christopher, M.9, Vajda, Vivi.12

1Western Australian – Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Perth WA, Australia 2 Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA 3,1 Department of Organic Geochemistry, Institute of Geoscience, Christian-Albrechts-University, Kiel, 24118, Germany 4Geochemistry & Isotope Biogeochemistry Group, Department of Marine Geology, Leibniz Institute for Baltic Sea Research, 18119 Warnemünde, Germany 5Marine Geochemistry, University of Greifswald, 17489 Greifswald, Germany 6Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, 18059 Rostock, Germany 7Department of Geosciences, Pennsylvania State University, University Park, PA, USA 8School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK 9Institute for Geophysics, Jackson School of Geosciences, University of Texas, Austin, TX, USA 10Department of Earth Sciences and Engineering, Imperial College London, UK 11Department of Geosciences, University of Alaska, Fairbanks, AK, USA 12Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden

The Chicxulub crater (Yucatán Peninsula, Mexico) was formed by an asteroid impact 66 Ma ago and is thought to have caused the Late Cretaceous mass extinction event (e.g. Schulte et al., 2010, Hildebrand, 1991) which led to 76% loss of species world-wide including non-avian dinosaurs (Sepkoski, 1986). Also a collapse in phytoplankton productivity in the world’s oceans occurred due to a lack of sunlight (Zachos and Arthur, 1986). In 2016, the peak ring of the Chicxulub crater core was recovered by the International Ocean Discovery Program and International Continental Drilling Program Expedition 364 (“Chicxulub: Drilling the K-T Impact Crater”). Samples from this core were extracted and analysed for lipid biomarkers and stable isotopes.

Lipid biomarker profiles were used to reconstruct the origin, recovery and development of non-fossilized microbial life forms and the associated paleoenvironmental conditions in the crater from the days after the impact to up to 4 million years. A tsunami that flooded the crater within a day after the impact (Gulick et al. 2019) deposited the upper part of the suevite sequence and carried debris containing cyanobacteria, archaea, dinoflagellates and all types of anaerobic photosynthetic sulfur bacteria, likely originating from microbialites that inhabited the coast of the carbonate platform prior to impact site. The redeposited coastal cyanobacteria predominantly were diazotrophic heterocystous bacteria of the order Nostocales, as evidenced by their characteristic C26-glycolipids. The coastal anaerobic sulfur bacteria were composed of Chlorobiaceae and Chromatiaceae, revealed by the presence of their specific biomarkers from carotenoid pigments (Schaefer et al., 2020). In addition, re-deposited terrestrial organic matter was degraded in situ in the tsunami layer by fungi, as evidenced by enhanced concentrations of perylene (cf. Grice et al., 2009).

As tsunami energy declined, land-derived material and nutrients fed the crater’s microbial ecosystem for the following ca. 30 kyr and led to non-heterocystous pelagic cyanobacterial blooms, recognized by the presence of 2a-methylhopanes. A major change towards an oligotrophic sea occurred 200 kyr after impact supporting nitrogen-fixing heterocystous cyanobacteria (Schaefer et al., 2020). The cyanophyte community structure by then had changed and diversified, as recognized by the occurrence of C32-heterocystous glycolipids, abundant in cyanophytes of the order Stigonematales. About 300 kyr after the impact with the onset of the Danian-C2 hyperthermal event (~65.7 Ma ago) during deposition of hemipelagic limestones abundant carotenoid biomarkers of photosynthetic sulfur bacteria suggests that the water-column in the crater became episodically stratified allowing for the development of photic zone euxinia.

The microbial life near the Chicxulub crater recovered quickly under harsh conditions post impact and subsequently continued to experience rapid changes in environment.


Gulick, S., et al., 2019. First Days of the Cenozoic PNAS, 116, 19342-19351.

Grice et al., 2009. New insights into the origin of perylene in geological samples. Geochimica et Cosmochimica Acta, 73, 6531-6543.

Hildebrand, A. R. et al., 1991. Chicxulub crater: a possible Cretaceous/Tertiary boundary impact crater on the Yucatan Peninsula, Mexico. Geology 19, 867-871.

Schaefer, B., et al. 2020. Microbial life in the nascent Chicxulub crater. Geology, 48, 328-332.

Schulte, P., et al. 2010. The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary. Science 327, 1214-1218.

Sepkoski, J. J., 1996. In: Global events and event stratigraphy in the Phanerozoic.  pp. 35-51, Springer.

Zachos, J., Arthur, M., 1986. Paleoceanography of the Cretaceous/Tertiary boundary event: inferences from stable isotopic and other data. Palaeogeography & Palaeoclimatology 1, 5-26.


Kliti Grice holds an Honours degree in Applied Chemistry. She has a PhD from the University of Bristol UK and is a John Curtin Distinguished Professor of Organic and Isotope Geochemistry at Curtin University (Perth, WA, Australia) and is the Founding Director of WA-Organic and Isotope Geochemistry Centre. She is an internationally renowned organic geochemist, a Fellow of the Australian Academy of Science and an Honorary Fellow of the Geochemical Society and European Association of Geochemistry. She creatively combines geological information with data on molecular fossils and their stable isotopic compositions (carbon, hydrogen and sulfur). Research applications are largely concerned with studying the dynamics of microbial, fungal and floral inhabitants to catastrophic events (e.g., wild-fire, tsunamis, volcanism, meteorite impacts) to evaluate the ecological health of ancient (paleoenvironments) and modern environments. Her research has focused on many of the big five mass extinctions: end-Permian, end-Triassic, end-Devonian and end-Cretaceous events. She also investigates the role of microbial communities in exceptional fossil preservation including finding the oldest intact dietary sterols in the geological record.

Hydrocarbons in a new early Paleocene sedimentary section recovered from the Campbell Plateau, south of New Zealand, by IODP Expedition 378

George, Simon C.1, Ausín, Blanca2, Childress, Laurel B.3, Röhl, Ursula4, Thomas, Deborah J.5, Hollis, Christopher J.6, and the IODP Expedition 378 Science Party

1Department of Earth and Environmental Sciences, Macquarie University, Sydney, Australia 2Department of Geology, University of Salamanca, Spain 3International Ocean Discovery Program, Texas A&M University, USA 4MARUM, University of Bremen, Germany 5College of Geosciences, Texas A&M University, USA 6GNS Science, New Zealand

The Cenozoic era in the South Pacific is poorly known through rather sparse drilling. International Ocean Discovery Program (IODP) expedition 378 “South Pacific Paleogene Climate” took place offshore New Zealand from January to February 2020. Expedition 378 recovered the first continuously cored, multiple-hole Paleogene sedimentary section from the southern Campbell Plateau at Site U1553. This high-southern latitude site builds on the legacy of Deep Sea Drilling Project (DSDP) Site 277, a single, partially spot cored hole, providing a unique opportunity to refine and augment existing reconstructions of the past ~66 My of climate history. Multiple cored intervals were likely recovered from the Eocene–Oligocene transition (EOT), the Middle Eocene Climatic Optimum (MECO) and other Eocene Thermal Maximum events, and the Paleocene–Eocene Thermal Maximum (PETM). Expedition 378 also discovered a new expanded Paleocene siliciclastic formation (Unit V) that had never been drilled before, with an unknown basal age.

Coring at Site U1553 reached a maximum depth of 584.3 mbsf and recovered a 581.16 m long sedimentary succession of deep-sea pelagic sediment of Pleistocene and Oligocene to early Paleocene age from the Campbell Plateau. The recovered sections comprise five lithostratigraphic units. About 4 m of Pleistocene foraminifer-rich nannofossil ooze (Unit I) overlies an expanded sequence (~200 m thick) of late Oligocene–early Oligocene nannofossil ooze with foraminifers (Unit II). The nannofossil ooze in Unit II gradually transitions into nannofossil chalk in Unit III over 50 m from ~175 to 225 mbsf. Lithification of carbonates continues downcore and results in limestone, categorized as Unit IV. Finally, the bottom ~100 m of the sediment column contains siliciclastic Unit V, characterized by alternating mudstone, sandy mudstone, and very fine to medium-grained sandstone.

Headspace gas analyses for the uppermost 480 m of Site U1553 indicated very low hydrocarbon concentrations, suggesting the lack of biogenic and/or thermogenic gas production or their upward migration. A sudden increase in methane concentration occurred at the transition from Unit IV to Unit V. The methane increase was accompanied by the detection of thermogenic hydrocarbons (C2, C3, and C4), suggesting in situ methane production, possibly by microbial activity, and upward migration of thermogenic gas. Additionally, the deeper Unit V cores had a strong hydrocarbon odour on the catwalk and after core splitting, and fluoresced under UV light. A sample of the deepest core in Hole D was placed in a glass vial immediately after on-board core splitting and covered with acetone, so as to obtain a signature of these hydrocarbons. This solvent mixture was analysed by gas chromatography-mass spectrometry, which has revealed the presence of a bimodal distribution of n-alkanes (maxima at n-C14 and n-C20). The sample also contains methylalkanes, isoprenoids, alkylcyclohexanes, alkylbenzenes, alkylnaphthalenes, alkylphenanthrenes, other polycyclic aromatic hydrocarbons, and high molecular weight biomarkers including hopanes and steranes. The distribution of these compounds is consistent with a mixed signature, from firstly a mature migrated hydrocarbon phase, and secondly from indigenous immature hydrocarbons from the rock matrix.


Professor Simon George is an organic geochemist and marine geoscientist. He works especially on research areas to do with the geochemical record of the early evolution of life, petroleum geochemistry, marine geoscience, and bioremediation in cold climates.

85,000 years of polar front, warm current variability, and ice rafting in contourites off southwest Ireland

Westgård, Adele1, Gallagher, Stephen J.1, Monteys, Xavier2, Foubert, Anneleen3, Rüggeberg, Andres3

1The University of Melbourne, Melbourne, Australia, 2Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4, Ireland, 3Department of Geosciences – Geology, University of Fribourg, Chemin du Musée 6, CH – 1700 Fribourg, Switzerland

Integrated Ocean Drilling Program Expedition 307 Site U1318B cored a 90 m thick Quaternary contourite sequence in the Porcupine Seabight in 423 m water depth to understand paleoenvironmental conditions of cold-water coral carbonate mound growth initiation. Two warm contour currents flow northwards in the Porcupine Seabight: the Eastern North Atlantic Central Water (ENACW, ~600 m) and the Mediterranean Outflow Water (MOW, ~1000 m). However, while much work has been carried out on the carbonate mound province in the area the palaeoenvironmental context of the surrounding contourites has received scant attention. This work analysed planktonic foraminiferal assemblages and ice rafted debris (IRD) variability in the upper 30 m of Site U1318B to interpret oceanographic variability related to contourite sedimentation, and interpret the extent and timing of the British Irish Ice Sheet (BIIS) over the last 85,000 years.  

Samples from Site U1318B were processed for foraminiferal analysis. Planktonic foraminiferal assemblages (>150 µm fraction) were used to interpret sea surface temperatures (SST). The presence of the polar front (SST <8˚C) in the region was characterised by >80% Neogloboquadrina pachyderma (%NPS). IRD (>150 µm) abundance was counted and plotted by source area. An age model was developed using a 14C date, a nannofossil datum (Emiliana huxleyi/Gephyrocapsa caribbeanica) and regional correlation to MD01-2461 using %NPS and magnetic susceptibility data and to the Lisicki & Raymo (LR2004) stack.

The upper 30 m of Site U1318B is typified by alternations of dark brown-grey, occasionally laminated mud and medium to coarse sand facies with erosional bases. Muddy sand layers, sand lenses and dropstones are common. Planktic foraminiferal data suggests that in the last 85 ka the polar front was south of Site U1318B (>80% NPS) ~24 ka, ~28 ka, from 35 to 37 ka, 40 to 66 ka and ~68 ka. %NPS reached 70-79% on several times suggesting intermittent polar conditions. Subtropical taxa are rare when NPS are common. Maxima (<12%) of subtropical taxa occur several times in the last 35 ka suggesting intermittent ENACW influence. The IRD are predominantly sourced from the BIIS area. Increased IRD yield coincides with decreased %NPS. IRD maxima do not coincide with %NPS maxima since ice rafting was related to melting. IRD concentration gradually decreased after the last glacial maximum (LGM) (~20 ka).

Presence of subtropical taxa in contourite facies suggest increased current activity during warm periods. These currents likely slowed/shut down in association with the North Atlantic Meridional Overturning Circulation during cold periods. Periods of increased IRD conc­entration suggest BIIS extent reached the SW continental margin of Ireland from late MIS 5 (~80 ka) to MIS 2 (~20 ka). Significant decrease in IRD concentration suggests the BIIS started to retreat from the Porcupine Seabight following the LGM at around 20 ka.


Adele Westgård is an early career micropaleontologist and paleoceanographer. She graduates with a Master of Science from the University of Melbourne in December 2020 and will then move home to Norway to commence her PhD. Adele is particularly interested in climate and ocean variability at high latitudes during glacial periods.

East Antarctic meltwater influx from the Wilkes Subglacial Basin since the Last Glacial Maximum as determined by beryllium isotopes

Behrens, Bethany1,2, Miyairi, Yosuke1, Sproson, Adam D.1, Yamane, Masako3, Yokoyama, Yusuke1,2,4

1Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan 2Graduate Program on Environmental Science, University of Tokyo, Komaba, Japan 3Institute for Space-Earth Environmental Research, Nagoya University, Furocho, Japan 4Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Hongo, Japan

The West Antarctic Ice Sheet (WAIS) and East Antarctic Ice Sheet (EAIS) contain an amount of ice equivalent to 3-5 m and 53 m sea level rise, respectively (1). The WAIS, as a largely marine-based ice sheet, is susceptible to changes in ocean temperatures and prone to retreat. Recent research has revealed that areas of the EAIS situated below sea level are also very sensitive to atmospheric and oceanic temperature changes and vulnerable to retreat (2, 3). The two largest subglacial basins in East Antarctica, the Wilkes and Aurora basins, hold a total ice mass equivalent to 28 m sea level rise (4), demonstrating that even a partial collapse of the EAIS would have a major effect on global sea level.

While we know the general timing of post-LGM glacial retreat around Antarctica, there is scarce data on specific locations with detailed, high-resolution records of ice sheet dynamics during the Holocene. Here we present meteoric beryllium-10 (10Be) analysis of a marine sediment core from the Adélie Basin, located on the continental shelf offshore the Wilkes Basin, extracted during IODP Expedition 318. Our record covers the most recent period of major Holocene ice sheet retreat, sea level rise, and increased atmospheric CO2 since the Last Glacial Maximum ice sheet retreat (5). The beryllium isotope data suggest oceanic or climatic changes occurred at ca. 9.8 ka, ca. 6.3 ka, and from ca. 4.1 ka. From prior research, we can conclude our high meteoric 10Be values at ~9.8 ka and ~6.3 ka are attributed to an open marine environment created by the retreat of grounded ice along with an increased influx of meltwater (6-8). The elevated concentration and frequency variation of meteoric 10Be values starting from ~4.1 ka indicate a change in regime, possibly linked to changes in climate.

(1) Wilson DJ, Bertram RA, Needham EF, van de Flierdt T, Welsh KJ, McKay RM, et al. Nature. 2018;561(7723):383-6.

(2) Hansen MA, Passchier S. Geo-Marine Letters. 2017;37(3):207-13.

(3) DeConto RM, Pollard D. Nature. 2016;531:591.

(4) Shen Q, Wang H, Shum C, Jiang L, Hsu HT, Dong J. Scientific reports. 2018;8(1):4477.

(5) Yokoyama Y, Esat TM, Thompson WG, Thomas AL, Webster JM, Miyairi Y, et al. Nature. 2018;559(7715):603-7.

(6) Yokoyama Y, Anderson JB, Yamane M, Simkins LM, Miyairi Y, Yamazaki T, et al. Proceedings of the National Academy of Sciences. 2016;113(9):2354.

(7) Valletta RD, Willenbring JK, Passchier S, Elmi C. Paleoceanography and Paleoclimatology. 2018;33(9):934-44.

(8) Behrens B, Miyairi Y, Sproson AD, Yamane M, Yokoyama Y. Journal of Quaternary Science. 2019;34(8):603-8.


Bethany is a PhD candidate at the Atmosphere and Ocean Research Institute, the University of Tokyo where she is analyzing beryllium isotope ratios of marine sediment cores extracted from the Southern Ocean and lake sediment cores from Tasmania to better understand ice sheet dynamics between glacial and interglacial periods.

The isotopic footprint of a submarine mineral system: Cr and Sr isotopes in the Iheya North hydrothermal field, Okinawa Trough (IODP expedition 331)

Lucy McGee1, Thomas Burke1, Juraj Farkas1, Bradley Cave1, Chris Yeats2

1Department of Earth Sciences, University of Adelaide, Adelaide, Australia 2Geological Survey of New South Wales, Department of Regional NSW, Maitland, Australia

‘Black smokers’, or submarine hydrothermal vents, represent sites of intense hydrothermalism. Such chimneys transport metals into the ocean where they precipitate as Fe, Pb, Zn and Cu sulfide minerals. However, the spatial footprint of these high-temperature processes transporting metals in marine environments is not well constrained. Legacy material from the 2011 IODP expedition 331 to the Iheya North hydrothermal field in the Okinawa Trough provide a unique opportunity to investigate the isotopic footprint of key metals in the hydrothermal system. The sample set is based on the analysis of four cores: one situated at the foot of an actively forming massive sulfide mound, one drilled at a background site located 1km away from the hydrothermal vents and two cores sampled between these sites, representing a high temperature vent and a lower temperature vent. Samples taken at various depths from the four cores represent a wide range of material, from unaltered distal marine clays, through hydrothermally altered clays and volcanic material, to massive sulfides.

Bulk digestions on 30 samples give a suite of trace element analyses which show large variations, particularly in transition metal element concentrations. SEM-MLA mapping of key samples show important interactions between sulfide phases and the presence of gypsum/anhydrite shows oxidation and reduction in the same sample. The large variation between magmatic and seawater endmembers in 87Sr/86Sr isotopic ratios provide an excellent opportunity to investigate the magmatic ‘footprint’ of the metalliferous hydrothermal system in marine settings and how far into the background this can be detected. Stable Cr isotopes have the potential to show important redox interactions during anticipated oxidation of hydrothermal Cr(III) species in marine settings into oxidised Cr(VI), and possible back-reduction to Cr(III).


Lucy is a high temperature geochemist with a background in volcanology and igneous geology. She enjoys using isotopes to constrain Earth System processes related to magmas and is currently interested in the processes of metal transport in active systems.

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