Karl Turekian, a giant in the field of geology who brought dynamism and energy to the Geology and Geophysics Department for over half a century, died of cancer in Branford, Conn., on March 15. He was 85.

Geologists and geochemists interviewed credited Turekian with overseeing the coming of age of modern geochemistry — a field that drew little attention before Turekian began teaching and researching oceanography at Yale in 1956. During his 57-year career at the University, Turekian, a Sterling Professor of geology and geophysics, collected countless accolades and participated in some of the most significant scientific research of the 20th century, including the study of the first lunar samples collected during the Apollo space mission — and colleagues said Turekian’s research brought him to the pinnacle of achievement in his field.

“The world has lost one of the greatest geoscientists who ever lived,” said Jay Ague, the current chair of Yale’s Department of Geology & Geophysics, in an email to the department dated March 15. “His influence is so large it is impossible to measure.”

Turekian’s research brought him to the frontiers of discovery regarding the origin of the solar system, the extinction of dinosaurs and climate change, among other issues. William Graustein GRD ’81, a former student of Turekian’s, said the professor was never intimidated by the scope and importance of the problems he confronted, adding that Turekian guided his lab to approach “the big questions.” Former students said Turekian was known for saying that “one good data point” could change the world.

During his illustrious research career, Turekian edited eight scientific journals, published hundreds of papers, authored five books and received awards including the V. M. Goldschmidt Medal of the Geochemical Society and the Maurice Ewing Medal of the American Geophysical Union. He chaired the Department of Geology and Geophysics during the 1980s and also served as president of the Geochemical Society and a member of the National Academy of Sciences.

Raised in an Armenian immigrant family and overcoming financial hardship, Turekian went on to receive one of the first doctorates in geochemistry at Columbia University in 1955 and become one of the first geoscientists to teach at Yale. His intellectual brilliance took him to academic heights, but he never forgot the humility instilled in him through his blue-collar upbringing, said his wife Roxanne.

Turekian’s wealth of scientific achievement was paralleled only by his “larger-than-life charisma,” said his son Vaughan.

“His science never got in the way of his humanity, and his humanity never got in the way of his science,” Graustein said.

Since his death, Turekian’s family members said they have received an outpouring of condolences from the generations of geoscientists that Turekian taught and mentored around the world.

For Turekian’s 70th birthday in 1997, many of his former students returned to campus to visit him, and each student brought a coffee mug from his or her respective institution — a reference to Turekian’s “coffee hours,” in which he would invite students and faculty of all levels to gather and discuss cutting-edge research.

“He made you feel that you were the center of the world,” his daughter Karla said. “He was like that with the students, believing in you when you didn’t necessarily believe in yourself.”

Karla said she felt she had “won the lottery” with Turekian as a father. Turekian’s wife, Roxanne, said Turekian was a devoted husband during their 51-year marriage.

Turekian is survived by his wife Roxanne, his children Karla and Vaughan, and two grandchildren, Aleena and Charles.