A Memory of Ice

Front matter

THE ANTARCTIC VOYAGE OF THE GLOMAR CHALLENGER

THE ANTARCTIC VOYAGE OF THE GLOMAR CHALLENGER

ELIZABETH TRUSWELL

Contents

Illustrations

Figure 1. Route of the Glomar Challenger on Leg 28, with numbered

Figure 1.2. Geological time scale, simplified after International

Preface

The formal organisation of ocean drilling to recover core samples from the floor of the ocean has been operating now for 50 years. Samples from the sea bed reveal much of the way the Earth works—its climates past and present; its active nature, including the origin of destructive earthquakes; and the evolutionary history of much of its biology. This is now the world’s largest international geoscience program.

‘The first sea-going vessel specifically designed for this program was the Glomar Challenger, the subject of this book. Glomar Challenger was launched in 1968 as part of the Deep Sea Drilling Project. After 1983, when that ship was scrapped, other vessels and other programs followed, becoming increasingly international and with improved technical capabilities. The dedicated drilling ships were the Resolution and the Chikyu; other vessels, other drilling platforms, were co-opted as necessary. Of the newer programs, the Ocean Drilling Program ran from 1983 to 2003; the Integrated Ocean Drilling Program from 2003 to 2013 when its successor, the International Ocean Discovery Program, replaced it. With time, the programs have become increasingly focused on particular problems in Earth science, contrasting with the early programs that were more broadly exploratory—a more ‘looking to see what’s there’ approach.

As the pioneer vessel of this early phase in our understanding of the oceans, the Glomar Challenger has achieved something of iconic status. It has been called ‘famous’, ‘pioneering’ and ‘a ship that revolutionised Earth science’. ‘The present volume is just one story of that iconic vessel, on which I was privileged to sail in the southern summer of 1972/73 on its first and most successful voyage into the waters close to Antarctica.

xi

Acknowledgements

I am grateful to ANU Press for giving me the opportunity to tell part of the Glomar Challenger story. Brian Kennett, as Chair of ANU Press’s Editorial Board for Science and Engineering, steered the book through its early stages. For editing and comments on an earlier version of the manuscript thanks go to Neville Exon and Bernadette Hince and to Geoffrey Hunt for careful copy editing. Two referees, Jo Whittaker of the University of Tasmania, and Kiyushi Suyehiro of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) provided valuable overviews of the manuscript.

Any mistakes in the text are my own.

I owe thanks to Professor Stephen Eggins of the Research School of Earth Sciences, The Australian National University, for providing me with the opportunity to work in that research environment; to Brian Harrold for assistance with photographs; to Lynne Bean for discussions and to Leanne Armand, Program Scientist for the Australian and New Zealand International Ocean Discovery Program Consortium, for much encouragement.

Clive Hilliker has been an efficient draughtsman. Jane Truswell helped with particular illustrations and technical advice. Thanks are due to the many individual authors who allowed the reproduction of their illustrations, and to the institutions who were most helpful in providing access to maps and photographs. Included here are Geoscience Australia (with special thanks to Alix Post); the National Library of Australia; the State Library of Victoria; the Mitchell Library of the State Library of NSW; the Royal Geographical Society, London; the Scott Polar Research Institute, Cambridge; Kew Gardens, London; and the Bristol Museum and Art Gallery, UK. In Japan thanks are due to JAMSTEC, Tokyo.

xiii xiv

In the United States I must thank the National Geographic Society, Lamont-Doherty Earth Observatory and the Estate of Marie Tharp, the Bureau of Medicine and Surgery and Princeton University Library.

Above all, I thank my shipmates on the Glomar Challenger, scientists, technicians, cooks, drillers and crew, for sharing the excitement of this voyage during long hours in laboratories, late night discussions, good cheer and the occasional social event. And for their abiding interest in the post cruise aspects of the science.

Glossary

Albedo The fraction of light or solar radiation that is reflected back from a surface. Light surfaces with a low albedo, such as vegetation, look dark; surfaces with a high albedo, such as snow or ice, look bright.

Antarctic Circumpolar Current (ACC) The major ocean current that flows around Antarctica from West to East, connecting all three oceans linked to the Antarctic Ocean, Pacific, Indian and Atlantic. Driven by strong westerly winds, it is sometimes called the West Wind Drift.

Benthic Referring to the ecological zone close to the sea bottom. Organisms living in this zone are called benthos.

Calve (verb) The breaking off of an iceberg from an ice shelf or glacier.

Camera lucida An instrument that uses the deflection of light rays through a glass prism so that images are reflected on paper ready for drawing.

Chert A hard grey rock resembling flint, a chemical sedimentary rock composed of microcrystalline quartz. Breaks with a conchoidal fracture and very sharp edges and has been used for tool-making.

Clast In geology clast refers to a fragment of geological debris—chunks or fragments broken off other rocks by weathering or erosion, including, but not confined to, plucking by glacial action.

Cobble A clast of rock of a particular size, larger than a pebble and smaller than a boulder.

Come on site To arrive at the site or locality to be drilled.

Continental rise The slope transitional between the deep ocean floor, or abyssal plain, and the continent’s edge.

Core A continuous, usually cylindrical section of rock or sediment.

XV xvi

A MEMORY OF ICE Coring The act of drilling to retrieve a core.

Coriolis effect The observed motion of oceanic or atmospheric currents resulting from the Earth’s rotation. Currents are deflected to the right in the northern hemisphere and the left in the southern hemisphere.

Deep Sea Drilling Project (DSDP) A scientific ocean drilling project that operated from 1968 to 1983 using the Glomar Challenger as the drilling ship.

Diatoms Microscopic unicellular or colonial organisms enclosed in a cell wall, or frustule, made of silica. They may inhabit the sea surface, or freshwater, or live in soils, even in ice. They dominate the phytoplankton and are large contributors to the primary production of the oceans.

Dredging Collecting sediment, rock or biological samples from the sea floor using a variety of sampling tools.

Drilling ship A vessel designed for exploratory offshore drilling, for scientific purposes or for oil and gas exploration.

Earth’s crust The crust is the outer, solid shell of the Earth, underlain by Earth’s mantle. The crust may be of oceanic or continental type. Oceanic rocks are made of dense, dark coloured rocks rich in iron and magnesium, such as basalt. Continental rocks are generally less dense, enriched in silicon, oxygen, aluminium and potassium; granite is typical.

Fantail The rear or aft end of a ship—the deck area over the stern.

Fixist With reference to continental drift, refers to the view or to persons believing that the position of the continents has remained fixed through time.

Foraminifera (Commonly called ‘forams’) A phylum or class of single-celled organisms with an external shell or test most commonly made of calcium carbonate. Some 40 per cent are planktonic, living at the sea surface, others live in brackish estuaries or salt marshes. They form an important part of the marine food chain.

Grampus Possibly refers to the killer whale, Orcinus orca. Usage here comes from HMS Challenger notes on maps showing dredging sites in the Southern Ocean.

GLOSSARY

Granule A large pebble or grain; a mineral fragment larger than a sand grain and smaller than a pebble.

Great Ice Barrier Usually refers to the Ross Ice Shelf. This usage dates from the HMS Challenger expedition and is mentioned in the ‘Aims’ of the Challenger voyage in 1874.

Greenhouse Earth A period in Earth history when there were no continental glaciers, the levels of carbon dioxide and water vapour were high, as were sea surface temperatures. Contrast Icehouse Earth.

Growlers Small icebergs showing 1 metre above the waterline.

Ice Age A period of low temperatures over the Earth, resulting in the expansion of the polar ice sheets and alpine glaciers. Within an ice age, such as that of the present Earth, individual periods of excessive cold are termed ‘glacial’, intervening warmer periods ‘interglacials’. The Great Ice Age historically refers to the present Pleistocene Epoch, when large ice sheets covered Europe and North America.

Ice belt On an icebreaker this refers to a reinforced zone in the hull, typically extending 1 metre above and below the waterline.

Iceberg A large piece of freshwater ice floating freely in the ocean. About 90 per cent of the iceberg is below water.

Icecap A thick continuous layer of ice covering a continent such as Antarctica—in that instance also referred to as the ‘Antarctic Ice Sheet’.

Icehouse Earth A period in Earth history when ice sheets are present— as currently at both poles. These may wax and wane between glacial and interglacial periods. Levels of carbon dioxide and water vapour are lower than in a greenhouse phase, and sea surface temperatures are significantly lower.

Ice islands An early term for icebergs; note references in James Cook’s account of his second voyage.

Ice-rafted debris (IRD) Rock material eroded from the continent, carried into the ocean and eventually dropped when icebergs melt. It may take the form of pebbles, cobbles or boulders, even sand.

xvii xviii

Ice sheet An extensive area of ice, usually covering land for a long time. Refers usually to those in Antarctica—e.g. East Antarctic or West Antarctic Ice Sheet—or to the Greenland Ice Sheet.

Ice shelf An extensive area of very thick ice, more or less flat and slowly moving, floating on the sea but attached on one side.

IODP [Integrated Ocean Drilling Program; later International Ocean Discovery Program.

IODP(1) Integrated Ocean Drilling Program (2003-2013). IODP(2) International Ocean Discovery Program (2013-2023).

Krill Any shrimp-like planktonic marine organisms in the order Euphausiacea.

Mobilist One who believes in change; with reference to the hypothesis of continental drift, refers to the view, or to those holding the view, who believe the position of the continents has changed through time. Compare fixist.

Moon pool The opening in the base of a ship’s hull that allows the drilling bit and drill string to pass through.

Moraine A ridge of rock debris deposited at the edge of a glacier; terminal moraines are deposited at the glacier front or snout; lateral moraines at its edge.

Nannofossils The term refers to the remains of coccoliths and coccospheres of marine algae. Coccolith refers to the disc-like plate secreted by the organism; these are often found separated and they accumulate in marine sediments as calcareous oozes.

ODP Ocean Drilling Program.

Ooze (noun) In a geological sense, deposits of soft mud on the sea floor, with their composition usually reflecting the microscopic remains of organisms that live at the sea surface. Includes diatom ooze, nannofossil ooze and foraminiferal ooze.

Palaeontologist A scientist who studies fossils.

GLOSSARY

Palaeothermometer Anything in the natural record that allows us to deduce the temperature conditions of past ages; ratios of different chemical isotopes are included, as are annual growth rings in trees or corals.

Palynologist A scientist who studies living and fossil pollen grains and plant spores. Derived from the Greek pa/uno—to strew or sprinkle.

Palynomorphs Organic-walled microfossils; includes pollen grains and spores, but also dinoflagellates.

Phytoplankton Microscopic marine algae—included here are diatoms, coccoliths, algae and bacteria. Dinoflagellates are loosely included, though these are not strictly algae. These form the base of the food chain for aquatic animals, and fix large amounts of carbon.

Pipe rack The structure on a drilling ship that supports and stores lengths of drill pipe.

Plate tectonics Refers to the scientific theory and study of the way in which tectonic plates (see) move and their interaction with each other.

Polar Front Commonly called the Antarctic Convergence—the zone separating the Antarctic and Subantarctic water masses or, more generally, the zone where cold surface waters from Antarctica sink beneath warmer waters to the north. In the Southern Ocean it is associated with the Antarctic Circumpolar Current.

Radiolaria Single-celled, microscopic protists with an amoeba-like body enclosed within a spiny, elaborate skeleton of silica.

Recycling, recycled With respect to sediment particles it reflects the mixing of older particles into younger sequences. Around Antarctica the action of glaciers is the key process in recycling in sediments. The term often applies to older fossils mixed in with younger forms.

Ross Ice Shelf The world’s largest body of floating ice, occupying the southern part of the Ross Sea. Named after James Clark Ross, who discovered the feature in 1841, and originally called The Barrier. The name was changed to Ross Ice Shelf by the US Board of Geographic Names in 1953, and published in 1956.

Sea-floor spreading Process by which molten magma from deep within the Earth rises at submarine ridges and spreads away from the ridge to form new sea floor.

xix

XX

Sedimentologist A scientist who studies modern or ancient sediments, such as sand, silt and clay, and their formation into sedimentary rock.

Silt A granular sedimentary material with particle sizes intermediate between sand and clay. May be deposited by water, ice and wind.

Sounding More formally ‘depth sounding’. Refers to measuring the depth of a body of water; this is usually applied to measurement with a line and sinker, but can refer now to ‘echo sounding’ using sound transmission.

Spudded in A term deriving from the oil exploration industry—refers to starting to drill a well or borehole; removing the initial rock debris from the site with the drill.

Subduction The process in plate tectonics wherein the edge of one plate slides beneath another. In the process the edge of one plate sinks into the Earth’s mantle.

Tectonic plate A massive slab of the Earth’s lithosphere—the Earth's crust and uppermost layer of the Earth’s mantle. They are usually made up of both oceanic and continental crust that floats on the Earth’s upper mantle.

Tillite Cemented or consolidated sediments of glacial origin, usually an unsorted mixture of clay, sand and boulders; unconsolidated deposits of the same material are called till.

Turbidites Sedimentary rocks formed by gravity flow. The term usually refers to deposits made within the deep ocean; the beds grade upwards from coarser to finer particles.