Brock University’s Distinguished Professor designation is a lifetime appointment recognizing outstanding achievement in each recipient’s academic discipline. This series of articles highlights this year’s recipients. Read more about the award and its recipients on The Brock News.

Martin Head has been digging deep into Earth’s geological record for decades, both figuratively and literally.

The Brock University Professor of Earth Sciences’ research is focused on stratigraphy, the study of how sediment layers can reveal aspects of planetary history, including significant shifts in Earth’s climate.

His work in this area includes refinements to the geological time scale, such as the highly publicized Anthropocene epoch.

For this, and other significant scientific contributions, Head was among 10 Brock professors recently recognized with the new honourary Distinguished Professor designation by the Office of the President.

Head uses the fossil record of a particular group of microplankton called dinoflagellates to help understand how climate has evolved over the last few millions of years.

Using sediment cores obtained from the bottom of the world’s oceans, Head and his students extract fossil dinoflagellates using acids that dissolve the sediment but not the organic-walled microfossils.

Under a microscope, the minute fossils tell a story of what the surface of the water was like when they were alive and reveal valuable information about the strength and positions of major ocean currents, and the global climate, back in geological time.

“The challenge is to extract the key signals from the sediment record — and they are always incomplete — and figure out what they mean,” says Head.

One species of dinoflagellate is characteristic of the North Atlantic Current. Head and his students have used this species to track changes in the North Atlantic Current over time, discovering that an abrupt southward deflection had occurred 2.6 million years ago.

“This tells us that the climate is not operating in a linear state,” he says. “There are tipping points, or switches, where one small factor has had an amplifying effect — in some cases, causing near irreversible change.”

Some of the fossil dinoflagellates are extinct and Head has given names to numerous new species and genera. He has been honoured with two named after him, Decahedrella martinheadii and Cristadinium headii.

He recently returned from a meeting in Madrid, Spain, where he successfully introduced new rules to the code that governs the naming of plants, fungi and algae.

Head, who chairs the International Nomenclature Committee on Fossils, says these new rules “extend the conceptual framework of nomenclature for algae, making it easier to name new fossil algae.”

His research on fossils has led him into the politically charged world of the geological time scale, a journey that began during his time in Cambridge, England, two decades ago.

The geological time scale distills 4.6 billion years into manageable subdivisions of time, offering a common language for geoscientists. Each unit is defined by a reference point in rock or sediment from around the world. Boundaries on the geological time scale usually represent changes in Earth’s climatic state.

Head has been involved in defining these units for more than two decades, including eight years leading an international body tasked with subdividing the past 2.6 million years, known as the Quaternary Period. He helped define most units of the Quaternary used today, including the Quaternary itself.

“These units are like chapters of a book, and piecing together the evidence to determine what caused a switch in Earth’s functional state, and why this happened, is an exciting challenge,” says Head.

A member of the Anthropocene Working Group since 2016, he is a leading proponent of formalizing the Anthropocene as a new epoch within the geological time scale.

“We left the functional state of the Holocene in the mid-20th century, and our new planetary state, driven by overwhelming impacts of the human enterprise, needs its own formal unit of geological time,” Head says.

He acknowledges that the Anthropocene’s brevity — only 72 years in duration — has met some resistance, but he says carbon dioxide levels have not been this high for three million years, when climates were much warmer than today.

“Given the amount of greenhouse gases already emitted, we are locked into global warming for tens of millennia,” he says.

Head and his colleagues are trying to understand these warm climates from deep time to get a better sense of where we’re heading.

“The past is the key to the future,” he says.

Head is consistently listed as one of the most highly cited scientists across all disciplines. The h-index rating measures the productivity and citation impact of a person’s publications. Head’s h-index is an outstanding 47 with Scopus, based on 169 documents, and 45 with the Science Citation Index, based on 144 documents.