John R. “Jack” Warne was born in Honolulu on March 20, 1929 to Robert Ellis “Bob” and Dorothy Dunbar (Head) Warne. Jack first met his father in Hong Kong six weeks after his birth. Bob and Dorothy then continued their voyage to Mindanao, in the Philippines, where Bob had started a pineapple plantation for Dole.

Geology and his wife Bonnie were the great loves of Jack’s life. He was intelligent, flirtatious, funny, and charming. He was also stubborn — he didn’t suffer fools gladly. Always an optimist and critical thinker, he never seemed old. He was curious about everything, constantly learning, and excited about sharing ideas. He often said “the more you learn, the more you find out you don’t know.” He routinely diagramed geological formations as he spoke and was working on presentations on geology and other topics into his final months. He instilled a life-long love of learning in his daughters.

Jack enjoyed and valued his family and friends. One grandchild spoke for many, saying, “He’s so good at making people laugh and making them feel loved and supported. He leads by example on how to love.” He made up collaborative stories for his children and grandchildren, and he went to elaborate lengths to give good parties. When we think of Jack, the word that most comes to mind is laughter.

Jack’s brothers Tom and Doug were born on Mindanao, where the family lived in a small group of five houses built by the plantation carpenter. In 1938 his family moved to Honolulu, Hawaii where Bob started an orchid nursery stocked with orchids he had collected in the Philippines and purchased from the best orchid growers everywhere they traveled on an around the world tour.They developed many new orchid crosses, including a little red orchid called the Jack Warne. All three boys worked potting, packing, and shipping orchids. Jack hated the work.

When attacks on Pearl Harbor began, they heard explosions and thought US pilots were being careless dropping dummy bombs. When his uncle Milton came asking for a scythe to use as a weapon, Bob said, “Why?” and Milton replied, “Haven’t you heard? They bombed Pearl Harbor!” During the war, school buildings were used by the military, and school was held half days. The Boy Scouts were asked to become bicycle messengers, and 12-year-old Jack volunteered. The family was set to evacuate on a navy ship when the battle of Midway was won. They decided to stay in Honolulu, and Jack graduated from Punahou (a private school founded for the children of missionaries and Hawaiian royalty) as senior class president.

At Stanford’s School of Mineral Science, Jack received his bachelor’s (1951) and master’s (1952) degrees in Geology. (He once said, “One lifetime is not enough for a geologist.”) He paid his tuition by hitchhiking to California flower shops and selling the flowers that his dad shipped from Honolulu.

During the Korean War, he joined the Naval Air Force as an officer and was stationed at Wright Patterson Air Force Base. There he married his Stanford girlfriend Corinne Sandberg. After his discharge in 1953, he went to work at Shell Oil Company. He requested an assignment to Denver, CO so Corinne could finish her degree in mathematics at the University of Denver. Their daughter Diane was born there, but they divorced in 1958.

Jack explored the front range of the Rocky Mountains extensively when with Shell, which had hired Swiss geologists (considered the top experts in mountain geology). Jack disagreed with their findings and never compromised his convictions when he knew he was right. He requested a transfer to Casper, Wyoming, but when bad weather diverted his plane from Casper it flew on to Billings, Montana. When he saw Billings, he knew that was where he wanted to live. In 1959, he left Shell and hung out his shingle as a consultant/independent geologist in Billings.

There he met Carolyn Grafton Rees, a teacher who had also lived and worked abroad, and they married in 1960. They had three daughters, Rees, Robin, and Julie Beth. The couple divorced in 1980.

He met Bonnie (Thaden) Bien in late 1980, and they married in 1983. They lived peacefully and joyfully together and had many adventures.

Through most of his professional life, Jack focused on exploration of oil and gas prospects, mainly in the Rocky Mountain states, and his work led to the development of more than 20 oil and gas fields in five states. Many of his major prospects were in lightly explored areas with little drilling, aiming for high-risk giant fields; this pioneer drilling contributed to the knowledge of structure, stratigraphy and source rocks in remote areas. In 2019, he was given the Uuno Sahinen Silver Medallion Award by the Montana Bureau of Mines and Geology at Montana Tech in recognition of his significant long-term contributions to promoting the orderly development of Montana’s groundwater, mineral and energy resources.

Jack’s curiosity and love of sharing ideas permeated all he did. Early in his career, Jack participated in a geology study group in Denver composed of researchers from major oil companies, the Colorado School of Mines, and the Colorado Geological Survey. He later organized a similar study group in Billings. As Chair of Continuing Education for the Montana Geological Society in the 1970s, he brought nationally recognized experts to conduct two-day workshops in Billings, covering new developments in structural geology, oil and gas source rocks, and sedimentation.

Jack was cited as a great mentor to his peers and to many generationally younger geologists. In the 1980s, Jack founded the UGLy (Unemployed Geologists Lunch-yun) Group of local geologists who met bi-weekly to share prospect ideas, knowledge, and friendship in a confidential environment. This allowed members to critique each others’ data and ideas before taking prospects on the road to sell. Members have faithfully carried on his UGLy luncheon tradition to this day, and Jack participated to the last. One member recalled that, after he was laid off by an oil company, Jack invited him to "consult" on some Thrust Belt seismic lines. “Jack knew more than I did about the seismic that I interpreted for him, but he still insisted on paying me for consulting work — a greatly appreciated check at a difficult time.”

Because geologists are dependent on a fluctuating oil market, he was sometimes broke, but he never gave up — there are many kinds of discoveries, and sometimes the rewards are intangible. He had a long collaboration on prospects with Irv Kranzler, and In an early joint project, they got someone with connections to Occidental Petroleum to drill a well north of Billings. Occidental was a private company at the time but was preparing to go public. The well tested oil at a high rate and was announced on the eve of the public offering. Occidental’s involvement in the well had a positive impact on the IPO. While the well depleted quickly, Occidental went on to do quite well. Jack and Irv claimed godfather status to Occidental, though it’s not clear whether that was a reciprocated acknowledgement.

Although most of his work is in confidential exploration reports and maps, Jack authored several field guides and road logs and led many field trips published by the Montana Geological Society, the Tobacco Root Geological Society, and the Rocky Mountain Section of the American Association of Petroleum Geologists. He is a past president of the Tobacco Root Geological Society and an active member of the Montana Geological Society and many other regional and national geological associations

He was also active in the community, including serving as President of the Board of Mayflower Congregational Church and of the Billings Unitarian Fellowship and as a founding member of the Billings Association of Humanists.

Jack is survived by his adored wife, Bonnie Warne, his four adventurous daughters, Diane Warne Anderson [Mike Habermann], Rees Warne [Joseph Kotun], Robin Warne, and Julie Beth Warne Wilson [Sean Wilson], and his well-loved grandchildren Christopher Anderson Jasmine, Malia, and Melody Warne Rowe, Sophia (Warne Rowe) Spencer, and Ivan, Miles, Bronwyn, and Taryn Wilson.

Jack Warne died peacefully at home on October 30, 2026, surrounded by his family. No services are planned. If you would like to do something in his memory, Jack suggested planting a tree.