In the summer of 1964, a Yale undergrad named J.G. Mead discovered a beaked whale fossil during an expedition in what is now the Turkana region of northwest Kenya. The 17-million-year-old fossil played an integral role in providing the first date estimate for East Africa’s puzzling tectonic uplift. Now, 56 years later, the fossil has become the impetus for new research that takes a unique approach to uncovering the course of mammalian evolution in East Africa.
In January 2021, an international research team led by Stony Brook University will launch a project that aims to understand how climate change and tectonics on Miocene ecosystems in this region influenced life and evolution, from the time that whale lived to the present day.
The research is supported by a $2.7 million four-year grant from the National Science Foundation’s (NSF) Frontier Research in Earth Sciences (FRES) Program. Named the Turkana Miocene Project, the research is multinational, interdisciplinary and involves five core U.S. universities. Led by Stony Brook, the project also includes Rutgers University, Hamilton College, the University of Michigan and the Lamont-Doherty Earth Observatory of Columbia University.
The international team includes experts in tectonics, sedimentology, geochronology, isotope geochemistry, paleoecology, climate modeling and paleontology, and includes members based at the National Museums of Kenya and University of Helsinki, Finland.
The goal of the research is to better define through fieldwork, laboratory analysis and advanced climate modeling how tectonics and climate interacted to shape the environment that gave rise to the ancestors of humans and our closest living relatives, the chimpanzees, gorillas and orangutans that emerged in Africa.
Since the whale fossil was originally found 740 miles inland and at an elevation of approximately 2,000 feet, the question of how it got to that location has mystified scientists for decades. And because it represents a profound change from the Miocene Epoch to Kenya’s Turkana Basin today — a possible indication of a transformed geological and ecological landscape — the Miocene is of particular interest to geologists and paleoclimatologists. That’s because major phases of the geology of the Himalayas occurred during the period, affecting monsoonal patterns in Asia that were interlinked with glacial periods in the northern hemisphere.
A longstanding question at the intersection of Earth and life sciences is: “What roles if any do climate and tectonics play in the evolution of life?”
“The East African Rift is among the best places to study the influences of Earth processes on the evolution of mammals,” said Isaiah Nengo, principal investigator, professor of anthropology and associate director of Stony Brook University’s Turkana Basin Institute. “Here, uniquely, the region’s geologic and climate histories, including the formation of the rift system that is the cradle of humankind, are preserved in sedimentary rocks. Our collaborative work will tease out how tectonics and climate come together to drive evolution.”
By investigating the basin’s sediments, the researchers will tackle a task that has never been done before. The team hopes the fossils contained will provide new insight into ancient climate and habitats that record the emergence of humans, their primate ancestors and African mammals over the past 25 million years.
It’s estimated that the human-chimpanzee common ancestor evolved approximately 7.5 million years ago (mya) and diverged from the common ancestor with the gorilla ancestor about 9.3 mya. Meanwhile, the common ancestor of the great apes and humans is estimated to have diverged from the ancestor of the gibbons and siamangs approximately 19.1 mya. All these key divergence events would have occurred in the time period known as the Miocene (from about 23 mya to 5 mya).
Nengo will collaborate with co-investigators Greg Henkes, an assistant professor in the Department of Geosciences at Stony Brook University, and Bill Holt, a professor of geophysics, Department of Geosciences, along with the international team. They will explore relationships between tectonics, climate and mammal evolution in the Turkana Basin using integrated field, laboratory and modeling studies. New and existing data will be combined to study the links between rift development, climate change and their respective roles in vegetation and mammal evolution.
The first two years of the initiative will focus on data collection from the field. The third year will involve laboratory analyses. In the fourth year, the team will conduct the analysis and be on site at the Turkana Basin Institute to produce a tectonic model that reconstructs rift evolution in this region of East Africa over the past 25 million years.
That tectonic model will be integrated with climate-vegetation models. Independent geological, geochemical, paleoecological and paleontological data will be used to validate these model outputs to distinguish the influences of tectonics and climate on the evolution of Turkana ecosystems and mammals.
“This integrated approach across geoscience subdisciplines is really the future of paleoenvironmental reconstruction,” said Henkes. “The challenge of separating commingled effects of climate, tectonics and evolution is incredibly complex. We hope to leverage the best of these different approaches to demonstrate that it’s possible, at least at the scale of a single, very important basin. The urge to understand how our hominid ancestors responded to environmental change is so obviously of the moment. When we are out in the field in Turkana, with such intense heat and aridity, it’s hard to not contemplate the role climate has already played in the human origins story. This project aims to bring clarity to that evolutionary context.”
“This is a very exciting time to be working on such an integrated project,” added Holt. “Computational tools are now advanced enough to model the driving forces that impacted the 4-D evolution of the rift system, while also taking into account the coupling with climate and the resulting erosion and sedimentation. It will be possible to test models that predict the landscape response to tectonic and climate factors, all while considering the key geological, geochemical, paleoecological and paleontological observations.”
NSF’s FRES also provides funding to complete extensive fieldwork that will provide training for a cohort of students and postdocs at Stony Brook University, Lamont, Rutgers, Michigan and Hamilton College.
The project also involves Tara Smiley, an assistant professor in the Department of Ecology and Evolution, and members of the Interdepartmental Doctoral Program in Anthropological Sciences (IDPAS) at Stony Brook.
The co-investigators include the following: Kevin Uno, Lamont associate research professor, Columbia; Craig Feibel, professor of geology and anthropology, Rutgers; Catherine Beck, assistant professor of geosciences, Hamilton College; Chris Poulsen, professor, associate dean for natural sciences, University of Michigan; and IDPAS faculty members Troy Rasbury, associate professor, Department of Geosciences, Stony Brook; Gabrielle Russo, assistant professor, Department of Anthropology, Stony Brook; Sidney Hemming, professor and chair, Lamont Earth Observatory, Columbia; Stephen Cox, associate research scientist, Lamont-Doherty Earth Observatory; Ali Bahadori, graduate student, Department of Geosciences, Stony Brook; Mae Saslaw, graduate student, Department of Geosciences, Stony Brook; Sara Mana, assistant professor, geological sciences, Salem State University; Mikael Fortelius, professor of evolutionary paleontology, University of Helsinki; Indrė Žliobaitė, assistant professor, Department of Computer Science, University of Helsinki; Guillaume Dupont-Nivet, professor, Department of Earth and Planetary Sciences, Rutgers University; Rahab Kinyanjui, senior research scientist, National Museums of Kenya; Patricia Princehouse, senior research associate, Institute for the Science of Origins, Case Western Reserve University; Ellen Miller, professor of physical anthropology, Wake Forest University; Francis Kirera, assistant professor of anatomy, Mercer University; Nasser Malit, associate professor, biological anthropology, State University of New York at Potsdam); Peter Ungar, distinguished professor, anthropology, University of Arkansas; and Liam Zachary, graduate student, anthropology, University of Arkansas.
Permission for field and laboratory research in Kenya is provided by the Kenya Government with the support of the National Museums of Kenya.
— Robert Emproto